JP2018105598A - Heat exchanger and process for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a uniform and superior-adhering coated film to be formed at outer surfaces of flat pipes and to restrict variation in adhering strength or thermal conductivity between the flat pipes and the fins, in a heat exchanger having flat pipes and fins bonded through adhesion and a process for manufacturing the same.SOLUTION: A process for manufacturing a heat exchanger (1) includes: a step of forming a spray film (50) containing zinc in such a way that a maximum roughness at an outer surface (11) of a flat pipe (10) becomes 10 to 25 μm; a step for forming a coat film (60) containing resin for adhering a fin (20) and the flat pipe (10) to the outer surface (11) of the flat pipe (10) formed with the spray film (50); and the step for bonding the fin (20) with the flat pipe (10) including a step for fitting the flat pipe (10) formed with the spray film (50) and the coat film (60) to an inserting part (21) of the fin (20) to bond the fin (20) and the flat pipe (10) through the coat film (60).SELECTED DRAWING: Figure 5

Description

  The present invention relates to a heat exchanger and a method for manufacturing the heat exchanger, and more particularly to a heat exchanger in which a flat tube and a fin are joined by adhesion and a method for manufacturing the heat exchanger.

  Conventionally, a heat exchanger used in an air conditioner or the like has a flat tube made of aluminum or an aluminum alloy and an aluminum or aluminum alloy fin in which an insertion portion into which the flat tube is fitted is formed. is there. As such a heat exchanger, as shown in Patent Document 1 (Japanese Patent No. 5727299), a coating film is formed by applying an adhesive containing an adhesive resin to the outer surface of a flat tube. There are some which are joined by fitting a flat tube in which the fin is inserted into a fin insertion portion and bonding the fin and the flat tube through a coating film.

  In the heat exchanger of Patent Document 1 and the manufacturing method thereof, it cannot be said that the adhesiveness of the adhesive to the flat tube is good, and the adhesive is uniformly applied to the outer surface of the flat tube. It is difficult to form a uniform and good adhesion film on the outer surface of the tube. For this reason, it becomes easy to generate | occur | produce variation in the adhesive strength and heat conductive performance between a flat tube and a fin.

  An object of the present invention is to provide a heat exchanger in which a flat tube and fins are bonded together by bonding and a method for manufacturing the same, so that a uniform coating film having good adhesion can be formed on the outer surface of the flat tube. This is to suppress variations in adhesive strength and heat conduction performance between the fin and the fin.

  The manufacturing method of the heat exchanger concerning a 1st viewpoint has the process of forming a sprayed film, the process of forming a coating film, and the process of adhere | attaching a fin and a flat tube. Here, the step of forming the sprayed coating is a step of spraying a sprayed material containing zinc on the outer surface of the flat tube made of aluminum or aluminum alloy so as to have a maximum roughness of 10 to 25 μm. It is. The step of forming the coating film is a process of forming a coating film by applying an adhesive containing a resin that bonds the fin and the flat tube made of aluminum or aluminum alloy to the outer surface of the flat tube on which the sprayed film is formed. It is. The step of bonding the fin and the flat tube is a step of fitting the flat tube on which the sprayed film and the coating film are formed into the insertion portion formed on the fin and bonding the fin and the flat tube through the coating film. . Here, the maximum roughness is a value measured in accordance with JIS B 6001: 2001.

  Here, as described above, prior to forming the coating film on the outer surface of the flat tube, the sprayed film is formed on the outer surface of the flat tube so that the maximum roughness is 10 to 25 μm. That is, the coating film is formed on the outer surface of the flat tube on which the sprayed film is formed so that the maximum roughness is 10 to 25 μm. For this reason, here, the effect of preventing corrosion of the flat tube can be obtained by zinc contained in the sprayed film. In addition, here, by setting the maximum roughness of the outer surface of the flat tube on which the sprayed film is formed within a range of 10 to 25 μm, the surface roughness of the outer surface of the flat tube is improved in the adhesion of the coating film. The adhesive that forms a coating film on the outer surface of the flat tube can be applied uniformly, and the effect of forming a uniform and good adhesive film on the outer surface of the flat tube Can be obtained.

  Thereby, here, in the manufacturing method of the heat exchanger in which the flat tube and the fin are bonded together, it is possible to suppress variations in the bonding strength and the heat conduction performance between the flat tube and the fin.

  In the method for manufacturing a heat exchanger according to the second aspect, in the method for manufacturing a heat exchanger according to the first aspect, the sprayed film has a center line average roughness of 0.6 to 0.6 during the step of forming the sprayed film. It is formed on the outer surface of the flat tube so as to be 2.5 μm. Here, the center line average roughness is a value measured in accordance with JIS B 6001: 2001.

  Here, as described above, the surface roughness of the outer surface of the flat tube on which the sprayed film is formed not only has the maximum roughness within the range of 10 to 25 μm, but also the centerline average roughness is 0.6. By making it in the range of ˜2.5 μm, it is possible to further suppress variations in the adhesive strength and heat conduction performance between the flat tube and the fins.

  In the heat exchanger manufacturing method according to the third aspect, in the heat exchanger manufacturing method according to the first or second aspect, the step of forming the sprayed film sprays the spray material on the outer surface of the flat tube. A thermal spraying step and a diffusion step of raising the temperature of the flat tube after the thermal spraying step.

  Here, as described above, in forming the thermal spray film on the outer surface of the flat tube, not only the thermal spray material is sprayed on the outer surface of the flat tube, but also the temperature of the flat tube is increased to remove the thermal spray material from the flat tube. By diffusing to the outer surface, adhesion of the sprayed film to the outer surface of the flat tube can be improved and the outer surface of the flat tube can be contributed to within a desired surface roughness range.

  A method for manufacturing a heat exchanger according to a fourth aspect is the method for manufacturing a heat exchanger according to any one of the first to third aspects, wherein the adhesive has a higher thermal conductivity than the resin. Is included.

  As described above, when the coating film formed on the outer surface of the flat tube contains a heat conductive filler, the heat conduction performance between the fin and the flat tube bonded through the coating film is improved. However, since it tends to be difficult to uniformly apply an adhesive that forms a coating film on the outer surface of the flat tube, it tends to be difficult to form a uniform and adhesive film.

  However, here, as described above, prior to forming the coating film on the outer surface of the flat tube, the sprayed film is formed on the outer surface of the flat tube so that the maximum roughness is 10 to 25 μm. Yes. That is, since the coating film is formed on the outer surface of the flat tube on which the sprayed film is formed so that the maximum roughness is 10 to 25 μm, the adhesive containing the heat conductive filler is used. Therefore, the adhesive can be uniformly applied to the outer surface of the flat tube, and an effect of forming a uniform and good adhesive film on the outer surface of the flat tube can be obtained.

  A method for manufacturing a heat exchanger according to a fifth aspect is the method for manufacturing a heat exchanger according to any one of the first to fourth aspects, wherein after the step of bonding the fin and the flat tube, the tube axis of the flat tube And a step of joining the end portion of the flat tube to the header made of aluminum or aluminum alloy by brazing or welding.

  Here, as described above, the joining between the flat tube and the header requiring pressure resistance is performed by brazing or welding, unlike the joining by bonding the fin and the flat tube. For this reason, here, although the fin and the flat tube are joined by bonding, the heat conduction performance between the fin and the flat tube is good, and the pressure resistance at the joint between the flat tube and the header is high. A heat exchanger with good strength can be obtained.

  The heat exchanger manufacturing method according to the sixth aspect is the heat exchanger manufacturing method according to the fifth aspect, wherein an adhesive is applied to the end of the flat tube in the tube axis direction during the step of forming the coating film. The adhesive applied to the end of the flat tube in the tube axis direction is removed.

  When forming a coating film on the outer surface of the flat tube, if the adhesive is left applied to the end of the flat tube in the tube axis direction, the flat tube and header are joined by brazing or welding. The operation | work which removes the coating film formed in the edge part of the pipe axis direction of a flat tube is needed, and there exists a possibility of inhibiting brazing or welding operation | work.

  Therefore, here, as described above, when forming a coating film on the outer surface of the flat tube, no adhesive is applied to the end portion of the flat tube in the tube axis direction or applied to the end portion of the flat tube in the tube axis direction. The removed adhesive is removed. Thereby, here, the operation | work which joins a flat tube and a header by brazing or welding can be performed smoothly, and the productivity of a heat exchanger can be improved.

  A heat exchanger according to a seventh aspect includes a flat tube made of aluminum or an aluminum alloy, an aluminum or aluminum alloy fin formed with an insertion portion into which the flat tube is fitted, a thermal spray film, and a coating film. Have. The sprayed film contains zinc formed on the outer surface of the flat tube so that the maximum roughness is 10 to 25 μm. The coating film is formed on the outer surface of the flat tube on which the sprayed film is formed, and contains a resin that bonds the fin and the flat tube. Here, the maximum roughness is a value measured in accordance with JIS B 6001: 2001.

  Here, as described above, the coating film is formed on the outer surface of the flat tube on which the sprayed film is formed so that the maximum roughness is 10 to 25 μm. For this reason, here, the effect of preventing corrosion of the flat tube can be obtained by zinc contained in the sprayed film. In addition, here, by setting the maximum roughness of the outer surface of the flat tube on which the sprayed film is formed within a range of 10 to 25 μm, the surface roughness of the outer surface of the flat tube is improved in the adhesion of the coating film. Since it can be enlarged to such an extent, an effect of forming a uniform and good adhesive film on the outer surface of the flat tube can be obtained.

  Thereby, here, in the heat exchanger in which the flat tube and the fin are bonded together, it is possible to suppress variations in the bonding strength and the heat conduction performance between the flat tube and the fin.

  A heat exchanger according to an eighth aspect is the heat exchanger according to the seventh aspect, wherein the sprayed film is formed on the outer surface of the flat tube so that the center line average roughness is 0.6 to 2.5 μm. Has been. Here, the center line average roughness is a value measured in accordance with JIS B 6001: 2001.

  Here, as described above, the surface roughness of the outer surface of the flat tube on which the sprayed film is formed not only has the maximum roughness within the range of 10 to 25 μm, but also the centerline average roughness is 0.6. By making it in the range of ˜2.5 μm, it is possible to further suppress variations in the adhesive strength and heat conduction performance between the flat tube and the fins.

  A heat exchanger according to a ninth aspect is the heat exchanger according to the seventh or eighth aspect, wherein the coating film includes a heat conductive filler having higher heat conductivity than the resin.

  As described above, when the coating film formed on the outer surface of the flat tube contains a heat conductive filler, the heat conduction performance between the fin and the flat tube bonded through the coating film is improved. However, since it tends to be difficult to uniformly apply an adhesive that forms a coating film on the outer surface of the flat tube, it tends to be difficult to form a uniform and adhesive film.

  However, since the coating film is formed on the outer surface of the flat tube on which the sprayed film is formed so that the maximum roughness is 10 to 25 μm as described above, a thermally conductive filler is used as the adhesive. Despite the use of the inclusion, the adhesive can be uniformly applied to the outer surface of the flat tube, and the effect of forming a uniform and good adhesive film on the outer surface of the flat tube can be obtained. .

  A heat exchanger according to a tenth aspect is the heat exchanger according to any one of the seventh to ninth aspects, wherein the end of the flat tube in the tube axis direction is joined by brazing or welding. And a header made of metal.

  Here, as described above, the joining between the flat tube and the header requiring pressure resistance is performed by brazing or welding, unlike the joining by bonding the fin and the flat tube. For this reason, here, a heat exchanger having good heat conduction performance between the fin and the flat tube and also having good pressure strength at the joint between the flat tube and the header can be obtained.

  As described in the above description, according to the present invention, in a heat exchanger in which a flat tube and fins are bonded together by bonding and a manufacturing method thereof, a coating film that is uniform and has good adhesion on the outer surface of the flat tube. Can be formed, and variations in adhesion strength and heat conduction performance between the flat tube and the fin can be suppressed.

It is an external appearance perspective view of the heat exchanger concerning one Embodiment of this invention. It is a partial expanded sectional view (figure seen from the tube axis direction of a flat tube) of the heat exchanger in the central part vicinity of the tube axis direction of a flat tube. It is II sectional drawing of FIG. It is the elements on larger scale of the heat exchanger near the edge part of the pipe axis direction of a flat tube (figure seen along the pipe width direction of a flat pipe). It is a flowchart which shows the manufacturing method of a heat exchanger. It is a fragmentary sectional view (figure seen from the tube axis direction of a flat tube) of a flat tube in which a thermal spray film was formed in the outer surface. It is a figure which shows the change of the maximum roughness and centerline average roughness of the outer surface of a flat tube by the presence or absence of a thermal spray film. It is a fragmentary sectional view (figure seen from the tube axis direction of a flat tube) of the flat tube in which the thermal spray film and the coating film were formed in the outer surface. It is a figure (figure seen along the pipe width direction of a flat tube) which shows the end part of the pipe axis direction of a flat tube in which the thermal spray film and the coating film were formed in the outer surface. It is a partial expanded sectional view (figure seen from the tube-axis direction of a flat tube) which shows a mode that the flat tube in which the sprayed film and the coating film were formed in the outer surface was fitted and bonded to the insertion part of a fin. Partial enlarged view showing a state in which the end portion in the tube axis direction of a flat tube having a sprayed film and a coating film formed on the outer surface is inserted into the opening of the header and joined (viewed along the tube width direction of the flat tube) Figure).

  Embodiments of a heat exchanger and a method for manufacturing the same according to the present invention will be described below with reference to the drawings. In addition, the specific example of the heat exchanger concerning this invention and its manufacturing method is not restricted to the following embodiment, It can change in the range which does not deviate from the summary of invention.

(1) Configuration of Heat Exchanger FIG. 1 is an external perspective view of a heat exchanger 1 according to an embodiment of the present invention. FIG. 2 is a partially enlarged cross-sectional view of the heat exchanger 1 in the vicinity of the central portion of the flat tube 10 in the tube axis direction (a view seen from the tube axis direction of the flat tube 10). 3 is a cross-sectional view taken along the line II of FIG. FIG. 4 is a partially enlarged view of the heat exchanger 1 in the vicinity of the end portion of the flat tube 10 in the tube axis direction (a view seen along the tube width direction of the flat tube 10).

  The heat exchanger 1 mainly includes a plurality of flat tubes 10 made of aluminum or aluminum alloy, a plurality of fins 20 made of aluminum or aluminum alloy, and headers 30 and 40 made of aluminum or aluminum alloy. . The heat exchanger 1 is configured such that refrigerant flows in the flat tube 10 and air flows between the fins 20, and performs heat exchange between the refrigerant and air. When the refrigerant flows in the flat tube 10, the refrigerant is exchanged (branched or merged) with the flat tube 10 in the headers 30 and 40.

  The flat tube 10 has a flat shape in which a pair of flat surfaces 12 facing each other are formed on the outer surface 11, and a flat multi-hole tube in which a plurality of internal flow paths 13 including holes through which a refrigerant flows are formed. It is. The flat tube 10 is formed by extruding a metal material made of aluminum or an aluminum alloy.

  A sprayed film 50 containing zinc 51 is formed on the outer surface 11 of the flat tube 10. The thermal sprayed film 50 may include only zinc 51 or may include other metals (not shown) such as tin in addition to zinc 51. The film thickness of the sprayed film 50 is set to about 10 to 50 μm in consideration of the anticorrosive effect of the flat tube 10 and the like. The sprayed film 50 is formed on the outer surface 11 of the flat tube 10 so that the maximum roughness Rz is 10 to 25 μm. The sprayed film 50 is formed on the outer surface 11 of the flat tube 10 so that the center line average roughness Ra is 0.6 to 2.5 μm. Here, the maximum roughness Rz and the centerline average roughness Ra are values measured in accordance with JIS B 6001: 2001.

  Also, a coating film 60 including a resin 61 that bonds the fins 20 and the flat tube 10 is formed on the outer surface 11 of the flat tube 10 on which the sprayed film 50 is formed (that is, the outer surface of the sprayed film 50). Yes. The film thickness of the coating film 60 is set to about 20 to 50 μm in consideration of the contact area between the fin 20 and the flat tube 10, the degree of thermal resistance due to the coating film 60, and the like. Various resins can be used as the resin 61. For example, a thermosetting resin such as an epoxy resin is used. Further, the coating film 60 may further include a heat conductive filler 62 having a higher heat conductivity than the resin 61 (see FIG. 3). As the heat conductive filler 62, metal powder or ceramic powder can be used. Here, as the heat conductive filler 62, a material that hardly causes a chemical reaction with aluminum or aluminum alloy constituting the flat tube 10 and the fin 20 is preferable. For this reason, for example, aluminum powder, nickel powder or the like is used as the metal powder, and for example, aluminum oxide powder, aluminum nitride powder, silicon nitride powder or the like is used as the ceramic powder.

  The flat surface 12 is a tube step direction (FIG. 1) orthogonal to the tube axis direction of the flat tube 10 (direction of arrow X in FIGS. 1 to 4) and the tube width direction of the flat tube 10 (direction of arrow Y in FIGS. 1 and 2). (Direction of arrow Z of 4). The internal flow path 13 extends in the tube axis direction, and a plurality of internal flow paths 13 are arranged side by side in the tube width direction of the flat tube 10. Here, the tube axis direction (the direction of the arrow X), the tube width direction (the direction of the arrow Y), and the tube step direction (the direction of the arrow Z) are orthogonal to each other. A plurality of flat tubes 10 are arranged along the tube step direction. One end 14 in the tube axis direction of the flat tube 10 is connected to the header 30, and the other end 15 in the tube axis direction of the flat tube 10 is connected to the header 40.

  The fin 20 is a plate fin having a thin plate shape. The fin 20 is formed by subjecting a metal plate made of aluminum or an aluminum alloy to press working or the like. Here, since the fin 20 is formed using a metal material having a hydrophilic film formed on the surface, a hydrophilic film (not shown) is formed on the surface of the fin 20.

  A plurality of fins 20 are arranged at intervals in the tube axis direction. In addition, the fin 20 is formed with an insertion portion 21 into which the flat tube 10 is fitted. Here, the insertion portion 21 is a notch extending from one end of the fin 20 on the tube width direction side to the front of the other end in the tube width direction. Accordingly, the flat tube 10 can be fitted into the insertion portion 21 by being inserted from one end in the tube width direction of the fin 10 toward the other end side in the tube width direction. In addition, the insertion part 21 is not limited to what consists of such a notch, The hole which penetrates the fin 20 may be sufficient (In this case, the flat tube 10 is inserted from the tube-axis direction of the fin 10). become). And the fin 20 and the flat tube 10 are joined by adhesion | attachment through the coating film 60. FIG. Here, a collar portion 22 rising from the fin surface in the tube axis direction is formed around the insertion portion 21, and the collar portion 22 of the fin 20 and the flat tube 10 are bonded together via the coating film 60. Yes. Further, in order to improve the heat exchange performance and the like, the fins 20 are provided with irregularities 23 by cutting and raising the fin surfaces.

  The headers 30 and 40 have a cylindrical shape extending in the tube step direction, and are header tanks in which a plurality of openings 31 and 41 into which both end portions 14 and 15 in the tube axis direction of the flat tube 10 are inserted are formed. Both ends 14 and 15 in the tube axis direction of the flat tube 10 are joined to the headers 30 and 40 by brazing or welding while being inserted into the openings 31 and 41 of the headers 30 and 40. In this way, both ends 14 and 15 in the tube axis direction of the flat tube 10 are connected to the headers 30 and 40, and the internal space of the headers 30 and 40 and the internal flow path 13 of the flat tube 10 are in communication. ing.

(2) Manufacturing method of heat exchanger The manufacturing method of the heat exchanger 1 which has the structure demonstrated above is demonstrated using FIGS. Here, FIG. 5 is a flowchart showing a method for manufacturing the heat exchanger 1. FIG. 6 is a partial cross-sectional view of the flat tube 10 in which the sprayed film 50 is formed on the outer surface 11 (a view seen from the tube axis direction of the flat tube 10). FIG. 7 is a diagram showing changes in the maximum roughness Rz and the centerline average roughness Ra of the outer surface 11 of the flat tube 10 depending on the presence or absence of the sprayed film 50. FIG. 8 is a partial cross-sectional view of the flat tube 10 in which the sprayed film 50 and the coating film 60 are formed on the outer surface 11 (a view seen from the tube axis direction of the flat tube 10). FIG. 9 is a diagram showing end portions 14 and 15 in the tube axis direction of the flat tube 10 in which the sprayed film 50 and the coating film 60 are formed on the outer surface 11 (viewed along the tube width direction of the flat tube 10). It is. FIG. 10 is a partial enlarged cross-sectional view showing a state in which the flat tube 10 having the sprayed film 50 and the coating film 60 formed on the outer surface 11 is fitted and bonded to the insertion portion 21 of the fin 20 (the tube axis direction of the flat tube 10). Figure seen from). FIG. 11 shows a state in which the ends 14 and 15 of the flat tube 10 in which the sprayed film 50 and the coating film 60 are formed on the outer surface 11 are inserted and joined to the openings 31 and 41 of the headers 30 and 40. FIG.

  The manufacturing method of the heat exchanger 1 mainly includes a step (ST1) of forming the sprayed film 50, a step (ST2) of forming the coating film 60, and a step of bonding the fin 20 and the flat tube 10 (ST3). And a step (ST4) of joining the flat tube 10 and the headers 30 and 40 to each other.

  First, in the step (ST1) of forming the sprayed film 50, as shown in FIG. 6, the outer surface 11 of the flat tube 10 made of aluminum or aluminum alloy contains zinc 51 (not shown in FIG. 6). The sprayed film 50 is formed by spraying the material.

  Specifically, a flat tube 10 formed by extrusion or the like is prepared. And in order to form the sprayed film 50 containing the zinc 51 in the outer surface 11 of the flat tube 10, a thermal spray material is sprayed on the outer surface 11 of the flat tube 10 (spraying process). Here, as the thermal spray material, one containing only zinc 51 or one containing other metal (not shown) such as tin in addition to zinc 51 is used. Further, as a thermal spraying method in this thermal spraying process, various methods such as a flame spraying method and an arc spraying method can be adopted. Thereafter, in order to improve the adhesion of the sprayed film 50 to the outer surface 11 of the flat tube 10, the temperature of the flat tube 10 is increased after the spraying step (diffusion step). For example, the diffusion step may be performed at a temperature of about several hundreds of degrees centigrade for about several hours, and can be performed by placing the flat tube 10 in which the thermal spray material is sprayed on the outer surface 11 in a heating furnace. It is. In this way, the sprayed film 50 is formed on the outer surface 11 of the flat tube 10. The zinc 51 contained in the sprayed film 50 can provide an effect of preventing the flat tube 10 from being corroded.

  In addition, here, the surface roughness of the outer surface 11 of the flat tube 10 is increased by forming the sprayed film 50 on the outer surface 11 of the flat tube 10 having a small surface roughness (see the triangular points in FIG. 7). ing. Here, the sprayed film 50 is formed on the outer surface 11 of the flat tube 10 so as to have a maximum roughness Rz of 10 to 25 μm by the above-described spraying process and diffusion process (see the round points in FIG. 7). In addition, here, the sprayed film 50 is formed on the outer surface 11 of the flat tube 10 so that the center line average roughness Ra is 0.6 to 2.5 μm (see the round dots in FIG. 7). As described above, the range of the maximum roughness Rz and the centerline average roughness Ra (the range surrounded by the thick line in FIG. 7) is defined as the adhesion of the coating film 60 to the outer surface 11 of the flat tube 10. This is to increase the surface roughness to such an extent that the properties can be improved. Here, in forming the sprayed film 50 on the outer surface 11 of the flat tube 10, the diffusion process is performed after the spraying process. However, when only the spraying process is performed, the spraying process and the diffusion process are performed. In the same manner as described above, when a desired surface roughness range (a range of the maximum roughness Rz or a range of the centerline average roughness Ra) can be obtained, the diffusion step may be omitted (the square in FIG. 7). See dot). Further, when the diffusion process is performed after the thermal spraying process, the maximum roughness Rz and the centerline average roughness Ra tend to be smaller than when only the thermal spraying process is performed (circle points and squares in FIG. 7). If this tendency is utilized, the outer surface 11 of the flat tube 10 is brought into a desired surface roughness range (the range of the maximum roughness Rz and the range of the centerline average roughness Ra). Can contribute.

  Next, in the step (ST2) of forming the coating film 60, as shown in FIGS. 8 and 9, the aluminum 20 or aluminum alloy fin 20 and the flat surface are formed on the outer surface 11 of the flat tube 10 on which the sprayed film 50 is formed. The coating 60 is formed by applying an adhesive containing a resin 61 (not shown in FIGS. 8 and 9) that bonds the tube 10.

  Specifically, the flat tube 10 on which the sprayed film 50 is formed is cut so as to have a predetermined length according to the size of the heat exchanger 1 to be manufactured. Then, an adhesive is applied to the outer surface 11 of the cut flat tube 10. That is, an adhesive is applied to the surface of the sprayed film 50. Here, an adhesive is applied to a portion of the surface of the sprayed film 50 corresponding to the flat surface 12 of the flat tube 10. However, the end portions 14 and 15 in the tube axis direction of the flat tube 10 are not coated with adhesive or bonded so that the flat tube 10 and the headers 3 and 40 described later are not hindered from joining. After the agent is applied, it is removed. Note that, unlike the above, an adhesive may be applied before the flat tube 10 is cut. In this case, after the flat tube 10 to which the adhesive is applied is cut to a predetermined length, the adhesive applied to the ends 14 and 15 in the tube axis direction of the flat tube 10 is removed. Good. In addition, here, a thermosetting resin such as an epoxy resin is included as the resin 61 as the adhesive. In addition, here, in order to improve the heat conduction performance between the fin 20 and the flat tube 10 bonded via the coating film 60, not only the resin 61 but also the heat conductive filler 62 (FIG. 8) is added to the adhesive. , 9 (not shown).

  Here, prior to forming the coating film 60 on the outer surface 11 of the flat tube 10, as described above, the sprayed film 50 is applied to the outer surface 11 of the flat tube 10 so that the maximum roughness Rz is 10 to 25 μm. (See the round and square points in FIG. 7). That is, the coating film 60 is formed on the outer surface 11 of the flat tube 10 on which the sprayed film 50 is formed so that the maximum roughness Rz is 10 to 25 μm. For this reason, the surface roughness of the outer surface 11 of the flat tube 10 is increased to such an extent that the adhesion of the coating film 60 becomes good. As a result, the adhesive that forms the coating film 60 on the outer surface 11 of the flat tube 10 can be uniformly applied here, and the coating film 60 having a uniform and good adhesion is formed on the outer surface 11 of the flat tube 10. Effect can be obtained. Further, the surface roughness of the outer surface 11 of the flat tube 10 on which the sprayed film 50 is formed not only has the maximum roughness Rz in the range of 10 to 25 μm, but also the centerline average roughness Ra is 0.6 to Since it is in the range of 2.5 μm, the adhesion of the coating film 60 is further improved. On the other hand, when the sprayed film 50 is not formed on the outer surface 11 of the flat tube 10 (see the triangular point in FIG. 7), the surface roughness with a maximum roughness Rz of less than 10 μm is small. The adhesive that forms the coating film 60 on the outer surface 11 of the flat tube 10 cannot be uniformly applied, and the effect of forming the uniform and good adhesive film 60 on the outer surface 11 of the flat tube 10 cannot be obtained.

  Here, as described above, the heat conductive filler 62 is included in the coating film 60 formed on the outer surface 11 of the flat tube 10. That is, the heat conductive filler 62 is included in the adhesive forming the coating film 60. For this reason, since the tendency which becomes difficult to apply | coat uniformly the adhesive agent which forms the coating film 60 on the outer surface 11 of the flat tube 10 appears, it exists in the tendency for it to become difficult to form the coating film 60 with uniform and good adhesiveness. . However, here, prior to forming the coating film 60 on the outer surface 11 of the flat tube 10 as described above, the sprayed film is formed so that the maximum roughness Rz is 10 to 25 μm on the outer surface 11 of the flat tube 10. 50 is formed. That is, since the coating 60 is formed on the outer surface 11 of the flat tube 10 on which the sprayed film 50 is formed so that the maximum roughness Rz is 10 to 25 μm, the adhesive contains the heat conductive filler 62. Can be applied uniformly to the outer surface 11 of the flat tube 10, and the effect of forming a uniform and good adhesive film 60 on the outer surface 11 of the flat tube 10 is obtained. be able to.

  Next, in the step (ST3) of bonding the fin 20 and the flat tube 10, as shown in FIGS. 2, 3, and 10, the sprayed film 50 and the coating film 60 are formed on the insertion portion 21 formed on the fin 20. The formed flat tube 10 is fitted, and the fin 20 and the flat tube 10 are bonded via the coating film 60.

  Specifically, the fin 20 formed by press working or the like is prepared. And the flat tube 10 in which the sprayed film 50 and the coating film 60 were formed is inserted in the insertion part 21 formed in the fin 20. Thereafter, the assembly in which the flat tube 10 is fitted into the fin 20 is heated to a temperature (for example, about 100 to 300 ° C.) at which the resin 61 contained in the coating film 60 is cured to cure the coating film 60. The fin 20 and the flat tube 10 are bonded through the film 60. Here, the collar portion 21 of the fin 20 and the flat surface 12 of the flat tube 10 are bonded via the coating film 60. If the heating temperature is at this level, the fin 20 and the flat tube 10 can be joined without degrading the hydrophilic film formed on the surface of the fin 20.

  Here, as described above, since the uniform and good adhesive film 60 is formed on the outer surface 11 of the flat tube 10 through the sprayed film 50, the adhesive strength between the flat tube 10 and the fin 20 is increased. In addition, the fin 20 and the flat tube 10 can be bonded together in a state where variations in heat conduction performance are suppressed.

  Next, in the step (ST4) of joining the flat tube 10 and the headers 30 and 40, as shown in FIGS. 4 and 11, the end portions 14 and 15 in the tube axis direction of the flat tube 10 are made of aluminum or an aluminum alloy. The end portions 14 and 15 of the flat tube 10 in the tube axis direction are joined to the headers 30 and 40 by brazing or welding.

  Specifically, headers 30 and 40 are prepared. Then, the end portions 14 and 15 in the tube axis direction of the flat tube 10 of the assembly in which the fin 20 and the flat tube 10 are bonded together are inserted into the openings 31 and 41 of the headers 30 and 40. Thereafter, the end portions 14 and 15 of the flat tube 10 in the tube axis direction are joined to the headers 30 and 40 by brazing or welding. Here, when brazing or welding, only the ends 14 and 15 in the tube axis direction of the flat tube 10 and the vicinity of the openings 31 and 41 of the headers 30 and 40 are heated, and the fin 20 and the flat tube By cooling the portion where 10 is bonded by the coating film 60, the temperature rise of the portion where the fin 20 and the flat tube 10 are bonded by the coating film 60 is minimized. Thus, the heat exchanger 1 in which the flat tubes 10 and the fins 20 are joined by bonding is manufactured.

  Here, the joining of the flat tube 10 and the headers 30 and 40 that require pressure strength is different from the joining by bonding the fins 20 and the flat tube 10, as described above, by brazing or welding. I have to. For this reason, here, although the fin 20 and the flat tube 10 are joined by bonding, the heat conduction performance between the fin 20 and the flat tube 10 is good, and the flat tube 10 and the header 30 are , 40 can be obtained in the heat exchanger 1 with good pressure strength at the joint portion.

  Here, as described above, when the coating film 60 is formed on the outer surface 11 of the flat tube 10, no adhesive is applied to the ends 14, 15 in the tube axis direction of the flat tube 10, or the flat tube 10 Since the adhesive applied to the end portions 14 and 15 in the tube axis direction is removed, this facilitates the operation of joining the flat tube 10 and the headers 30 and 40 by brazing or welding. The productivity of the heat exchanger 1 can be improved.

  The present invention can be widely applied to a heat exchanger in which a flat tube and fins are joined by adhesion and a method for manufacturing the same.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 10 Flat tube 11 Outer surface 14, 15 End part 20 Fin 21 Insertion part 30, 40 Header 50 Sprayed film 51 Zinc 61 Resin 60 Coating film 62 Thermally conductive filler

Patent No. 5727299

Claims (10)

The thermal spray film (50) is formed on the outer surface (11) of the flat tube (10) made of aluminum or aluminum alloy so as to have a maximum roughness of 10 to 25 μm by spraying a thermal spray material containing zinc (51). Process,
A coating film (60) is formed by applying an adhesive containing a resin (61) for bonding the fin (20) made of aluminum or aluminum alloy and the flat tube to the outer surface of the flat tube on which the sprayed film is formed. Forming a step;
Inserting the flat tube on which the sprayed film and the coating film are formed into the insertion portion (21) formed on the fin, and bonding the fin and the flat tube through the coating film;
With
Manufacturing method of heat exchanger. During the step of forming the sprayed film, the sprayed film is formed on the outer surface of the flat tube so that the center line average roughness is 0.6 to 2.5 μm.
The manufacturing method of the heat exchanger of Claim 1. The step of forming the sprayed film includes a spraying step of spraying the sprayed material on the outer surface of the flat tube, and a diffusion step of increasing the temperature of the flat tube after the spraying step.
The manufacturing method of the heat exchanger of Claim 1 or 2. The adhesive contains a thermally conductive filler (62) having a higher thermal conductivity than the resin.
The manufacturing method of the heat exchanger of any one of Claims 1-3. After the step of adhering the fin and the flat tube, the tube axial end of the flat tube is attached to the aluminum or aluminum alloy header (30, 40) in the tube axial end (14, 15) joining by brazing or welding,
Further equipped with,
The manufacturing method of the heat exchanger of any one of Claims 1-4. In the step of forming the coating film, the adhesive is not applied to the end of the flat tube in the tube axis direction, or the adhesive applied to the end of the flat tube in the tube axis direction is used. Remove,
The manufacturing method of the heat exchanger of Claim 5. A flat tube (10) made of aluminum or aluminum alloy;
A fin (20) made of aluminum or aluminum alloy in which an insertion portion (21) into which the flat tube is fitted is formed;
A sprayed coating (50) containing zinc (51) formed to have a maximum roughness of 10 to 25 μm on the outer surface of the flat tube;
A coating film (60) formed on an outer surface of the flat tube on which the sprayed film is formed, and including a resin (61) for bonding the fin and the flat tube;
With
Heat exchanger (1). The sprayed film is formed on the outer surface of the flat tube so that the center line average roughness is 0.6 to 2.5 μm.
The heat exchanger according to claim 7. The coating film includes a thermally conductive filler (62) having a higher thermal conductivity than the resin,
The heat exchanger according to claim 7 or 8. Aluminum or aluminum alloy headers (30, 40) in which ends (14, 15) in the tube axis direction of the flat tubes are joined by brazing or welding,
Further equipped with,
The heat exchanger according to any one of claims 7 to 9.

Images