JP2006038335A - Core part for heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve corrosion resistance of a heat transfer tube, and at the same time, to prevent remaining of a flux when brazing an outer fin and the heat transfer tube. <P>SOLUTION: The core part of the heat exchanger 1 comprises the heat transfer tube 4 not formed with a brazing material layer, and the outer fin 5 formed with a brazing material layer 35 arranged alternately with the heat transfer tube 4. The heat transfer tube 4 is formed with a flux layer 31 on a face of a side contacting the outer fin 5 by precoating the flux in a raw material stage. By this, by not forming a brazing material layer in the heat transfer tube 4, the corrosion resistance of the heat transfer tube 4 is improved, and amounts of a brazing material and the flux supplied during brazing are relatively reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger in which, for example, a tube and a tank used in a vehicle air conditioner are separate, and particularly relates to a structure of a tube, an inner fin, an outer fin, and the like constituting a core portion of the heat exchanger. .

  When brazing the components of the core part made of an aluminum alloy of a heat exchanger, a stable oxide film is formed on the surface of the aluminum alloy, which prevents the brazing. It is common to use flux (FLUX) in order to remove water and prevent reoxidation (see, for example, Patent Documents 1 to 3).

On the other hand, a mode in which flux is applied to the surface of the component part of the core part of the heat exchanger made of an aluminum alloy is intended for a tube formed by roll homing a sheet-like member. However, when a brazing material layer is provided on both surfaces of a sheet-like member, there is a material in which the brazing material layer is impregnated with a flux (see, for example, Patent Documents 1 and 2). In addition, there is a type in which a flux layer is separately formed by attaching a flux to one or both sides at the stage of a brazing filler metal sheet member made of a brazing alloy, and then both are brought into close contact by rolling (see, for example, Patent Document 3).
JP-A-6-315791 Special Table 2002-540244 Japanese Patent Laid-Open No. 7-185884

  However, if the brazing filler metal layer is formed on the tubes, outer fins, inner fins, etc. constituting the core part of the heat exchanger as in the inventions of these patent documents, significant erosion of the brazing filler metal occurs during the brazing heat treatment. Since (erosion) occurs, the corrosion resistance of the components having these brazing material layers is relatively deteriorated. Therefore, it is desirable to eliminate the formation of the brazing material layer as much as possible.

  Also, regarding the flux, if the flux remains in the surface of the core component even after brazing because the flux is excessive, there is a problem that the surface treatment property of the core component of the heat exchanger is reduced. In addition, the excess flux contaminates or damages the inside of the furnace and the jig, resulting in a disadvantage that the life of these brazing equipments and instruments is relatively shortened.

  Therefore, the present invention provides a core part of a heat exchanger that combines the improvement of the corrosion resistance of the core part component of the heat exchanger and the prevention of flux residue on the surface of the component part.

  The core part of the heat exchanger according to the present invention is composed of a part in which a brazing filler metal layer is formed and a part in which the brazing filler metal layer is not supplied with the brazing filler metal layer. The parts on which the brazing material layer is not formed are characterized in that a flux is applied to the surface by a coating process at the material stage. The component parts of the core portion of these heat exchangers are made of, for example, an aluminum alloy. Further, a part which is supplied with the brazing material from a part on which the brazing material layer is formed without forming the brazing material layer may have a sacrificial corrosion layer on the surface thereof. The component in which the brazing material layer is formed may be one in which the flux is not applied to the surface.

  More specifically, the heat exchanger tube includes a heat exchange tube in which a brazing material layer is not formed, and outer fins in which a brazing material layer is disposed alternately with the heat exchanger tube, and the heat exchanger tube is In the material stage, a flux is applied to one or both surfaces in contact with the outer fin by a coating process (claim 2). More specifically, a roll homing tube in which a brazing material layer is not formed and outer fins in which a brazing material alternately arranged with the roll homing tube is formed, and a flux is formed on the outer surface of the roll homing tube. Is pre-coated (claim 3).

  More specifically, it consists of a heat exchange tube having a brazing filler metal layer formed on the outer surface, and an outer fin on which the brazing filler metal layer arranged alternately with the heat exchanger tube is not formed. In the material stage, a flux is applied to the surface in contact with the heat exchanger tube by a coating process (claim 4).

  More specifically, the heat exchanger tube includes a brazing filler metal layer formed on the side surface of the heat exchange medium passage, and an inner fin inserted into the heat exchange medium passage of the heat exchanger tube. In the material stage, a flux is applied to the surface in contact with the heat exchanger tube by a coating process (Claim 5). More specifically, a roll homing tube having an inner fin is provided, and a flux is precoated on the inner surface of the inner fin or the roll homing tube. These heat exchanger tubes (roll homing tubes), core parts such as outer fins and inner fins are made of, for example, an aluminum alloy. In addition, these heat exchanger tubes (roll homing tubes), core parts such as outer fins and inner fins may have a sacrificial layer on the surface thereof. The heat exchanger tube (roll homing tube) and the component parts of the core portion such as the outer fins having the brazing material layer may not have flux applied to the surface thereof.

  According to the first aspect of the present invention, since the core portion of the heat exchanger is composed of a part in which the brazing material layer is formed and a part in which the brazing material layer is not formed, corrosion such as pitting corrosion occurs. By making a part where this is not appropriate a part in which this brazing material layer is not formed, the corrosion resistance of the part can be relatively improved. On the other hand, the brazing material is supplied from the part on which the brazing material layer is formed to the part on which the brazing material layer is not formed, and the oxide film on the surface of each core component part is the part on which the brazing material layer is not formed. Since the flux on the surface is removed by fluidization and reoxidation is prevented, it is possible to satisfactorily braze parts with the brazing material layer formed and parts without the brazing material layer formed. . And the amount of brazing filler metal and the amount of flux supplied for brazing are also viewed from the whole heat exchanger when the flux is not applied to the surface of the component formed with the brazing filler metal layer. It can be suppressed to the necessary minimum amount. Furthermore, since the thickness of the brazing material layer is eliminated as compared with the case where the brazing material layer is formed on all the core components of the heat exchanger, the size of the heat exchanger can be relatively reduced.

  In particular, according to the invention described in claim 2 or claim 3, since the brazing filler metal layer is not formed on the surface of the heat exchanger tube (roll homing tube), the heat exchanger tube (roll homing tube). In addition, the brazing material is supplied from the outer fin to the heat exchanger tube (roll homing tube) side, and the surface of the heat exchanger tube (roll homing tube) and the outer fin is relatively improved. Since the flux coated on the surface of the tube itself is fluidized and removed, and the oxidation film prevents reoxidation, the heat exchanger tube (roll homing tube) and the outer fin can be brazed well. It is. And the amount of brazing filler metal and the amount of flux supplied for brazing can also be suppressed to the minimum required amount as seen from the whole heat exchanger if no flux is applied to the outer fin. It is possible to prevent the brazing material and the flux from being excessively provided during brazing. Furthermore, since the thickness of the heat exchanger tube (roll homing tube) can be made relatively thin because of the absence of the brazing material layer, the width in the stacking direction of the heat exchanger tube and the outer fin of the heat exchanger Can be made relatively small. Furthermore, since there is no flux residue with respect to the outer fin, the surface treatment of the outer fin is made uniform.

  In particular, according to the invention described in claim 4, since the brazing filler metal layer is not formed on the surface of the outer fin, the corrosion resistance of the outer fin can be relatively improved, and the heat exchanger tube. As the brazing material is supplied from the outer fin to the outer fin side, the oxide film on the surface of the heat exchanger tube and outer fin is removed by fluidizing and removing the flux coated on the surface of the outer fin itself. The tube can be brazed well. And the amount of brazing filler metal and the amount of flux supplied for brazing can also be reduced to the minimum necessary in view of the heat exchanger as a whole when no flux is applied to the heat exchanger tube. Therefore, it is possible to prevent the brazing material and the flux from being excessively provided during brazing. Furthermore, since the thickness of the outer fin can be made relatively thin because of the absence of the brazing material layer, the surface area of the outer fin can be made relatively large, and the heat exchange capacity of the heat exchanger is improved. it can.

  In particular, according to the invention described in claim 5 or claim 6, since the brazing filler metal layer is not formed on the surface of the inner fin, the corrosion resistance of the inner fin can be relatively improved, The brazing material is supplied from the heat exchanger tube (roll homing tube) to the inner fin side, and the oxide film on the surface of the heat exchanger tube (roll homing tube) and the inner fin has a flux coated on the surface of the inner fin itself. Since it is removed by fluidization, the inner fin and the heat exchanger tube (roll homing tube) can be brazed well. And the amount of brazing material and the amount of flack supplied for brazing are also the minimum necessary in view of the heat exchanger as a whole when no flux is applied to the heat exchanger tube (roll homing tube). Therefore, it is possible to prevent the brazing material and the flack from being excessively provided during brazing. Furthermore, since the inner width of the heat exchange medium passage of the heat exchanger tube (roll homing tube) can be reduced by the amount not having the flux layer, the heat exchanger tube (roll homing tube) of the heat exchanger can be reduced. The width in the stacking direction between the outer fin and the outer fin can be relatively reduced.

  According to the invention described in claims 1 to 6, since the core component of the heat exchanger can be formed by using a material that has been pre-fluxed by a coating process, the heat exchanger It is possible to reduce the post-process of applying flux such as flux application by shower after temporary assembly. And the core component of the heat exchanger which does not have the other flux can delete the process itself which gives a flux. In addition, when the coating process by dipping is adopted, the amount of flux can be reduced to the minimum necessary compared to the application of the flux by the shower after the temporary assembly of the heat exchanger. Residues can be suppressed and the surface cleanliness can be maintained. Furthermore, in the formation of heat exchanger tubes (roll homing tubes), compared to the surface formation of the flux by transfer while forming by roll homing, when the coating treatment by dipping is adopted, the flux is evenly distributed on the surface. Therefore, it is possible to prevent unevenness of the flux. Furthermore, in the brazing between the heat exchanger tube (roll homing tube) and the inner fin, the residue of the flux in the heat exchanger tube (roll homing tube) can be suppressed.

  Embodiments of the present invention will be described below with reference to the drawings.

  A heat exchanger 1 shown in FIGS. 1, 2 and 3 is an example of a heat exchanger used in the present invention, and is used as an evaporator constituting a refrigeration cycle of a vehicle air conditioner, for example. The heat exchanger 1 is assembled by a furnace brazing method, and a pair of tanks 2 and 3, a plurality of heat exchanger tubes 4 communicating with the tanks 2 and 3, and the heat exchanger tubes 4, corrugated outer fins 5 that are alternately stacked, side plates 6, 6 that are disposed further outward than the outer fins 5 that are located at both ends in the stacking direction, and one end in the longitudinal direction of the tank 2. The connector 9 is configured. The connector 9 includes inlet / outlet portions 7 and 8 for heat exchange medium, and is connected to an expansion valve (not shown).

  The heat exchanger 1 allows a heat exchange medium sent from an expansion valve (not shown) to flow into the compartment 2 on the tank 2 side of FIG. 2 and 3, and in the process, heat is exchanged with the air passing between the outer fins 5, and finally, it is sent out from the compartment 2 on the tank 2 side in FIG. I have to.

  Among these, as shown in FIGS. 3 (a) and 4 (a), the heat exchanger tube 4 is opened at both longitudinal ends inserted into the tanks 2 and 3, and the heat exchange medium passage 14 is located inside. It is a flat tube formed and has an inner fin 15 accommodated therein. In this embodiment, the heat exchanger tube 4 has opposed flat portions 4a and 4b, a bent portion 4c at one end in the width direction, and a joining margin portion at the other end of the bent portion 4c. 4d.

  And in this embodiment, the inner fin 15 accommodated in the heat exchanger tube 4 is connected along one side edge of the heat exchanger tube 4 as shown in FIG. The flat plate portions 15b and 15c that are connected to the portion 15a through the connecting portion 15a and abut against the inner surfaces of the flat portions 4a and 4b of the heat exchanger tube 4 are opposed to the end portions of the flat plate portions 15b and 15c. The flat plate portions 15c, 15b projecting toward the substantially central portion of the flat plate portions 15c, 15b have abutting portions 15d that abut the inner surfaces of the opposing flat plate portions 15b, 15c. Thereby, the rigidity in the width direction of the single inner fin 15, the contact resistance against the force in the width direction at the contact portion between the inner fin 15 and the heat exchanger tube 4, and the restraint force in the thickness direction by the heat exchanger tube 4. Rigidity can be increased, and even when the heat exchanger tube 4 is cut with the inner fins 15 included, the inner fins 15 can be made difficult to shift.

  As described above, the tanks 2 and 3 are disposed so as to face each other at a predetermined interval. In this embodiment, the tanks 2 and 3 are formed by extrusion molding. The tanks 2 and 3 will be described with reference to FIG. 3B. The tanks 2 and 3 have a tube insertion hole forming surface 20A on which a tube insertion hole 19 into which the heat exchanger tube 4 is inserted is formed. Openings are formed at both ends in the longitudinal direction, and the openings are closed by caps 21 except for the connector 9 as shown in FIGS. In the tanks 2 and 3, a partition wall 22 extending along the stacking direction of the heat exchanger tubes 4 is formed integrally with the side portion 20, and thereby the inside of the tanks 2 and 3 extends along the ventilation direction. A compartment 23 and a compartment 24 are defined in parallel.

  However, these tanks 2 and 3 are structured in order to prevent the heat exchange medium from being bypassed between the compartments 23 and 24 due to poor brazing between the members constituting the partition walls and the members constituting the side portions. Therefore, the heat exchanger 1 is suitable for downsizing and cost reduction.

  On the other hand, the compartment 23 and compartment 24 of the tank 2 also have a configuration different from that of the tank 3 as shown in FIG. That is, the tank 2 is partitioned along the ventilation direction by the partition plate 25 inserted from the slit 26, and is divided into the compartments 23a, 23b or 24a, 24b. The compartment 23b and the compartment 24b communicate with each other through the communication passage 27 in order to make the flow of the heat exchange medium 4 passes.

  By the way, among the core components of the heat exchanger, the heat exchanger tube 4 is a roll formed by a roll homing method from one thin sheet-like member A made of a highly conductive metal such as an aluminum alloy. Homing tube. The outer fin 5 is formed by deforming one sheet-like member B made of a metal having good conductivity such as an aluminum alloy into a corrugated shape, and the inner fin 15 has good conductivity such as an aluminum alloy. It is formed by bending a single sheet-like member C made of metal a plurality of times. In addition, since the manufacturing method of these tubes 4 for heat exchangers, the outer fin 5, and the inner fin 15 is well-known except the one part process mentioned below, the whole description is abbreviate | omitted.

  In this embodiment, as shown in FIG. 5, in the heat exchanger tube 4, the brazing material layer is not formed on the outer surface of the core material 30, and the flux layer 31 is formed. The flux layer 31 is formed by applying a flux by pre-coating the flux at the stage of the raw sheet-like member A. Furthermore, a sacrificial corrosion layer 32 may be formed between the core material 30 of the heat exchanger tube 4 and the flux layer 31 in order to improve corrosion resistance. Although not shown in FIG. 5, the flux layer 31 may also be formed on the inner surface of the core material 30. On the other hand, the outer fin 5 joined to the heat exchanger tube 4 has a brazing material layer 35 formed on the surface of the core material 34. A flux layer is not formed on the outer fin 5.

  However, when the temporary assembly of the heat exchanger is heated, the brazing material of the outer fin 5 is fluidized and supplied to the outer surface side of the heat exchanger tube 4, while the outer fin 5 In addition, the oxide film on the outer surface of the heat exchanger tube 4 is removed by supplying the flux between the outer surface of the heat exchanger tube 4 between the outer fin 5 and the heat exchanger tube 4 by fluidization by heating. Therefore, the outer fin 5 and the heat exchanger tube 4 can be brazed satisfactorily in a minimum amount without producing an excessive brazing material.

  Moreover, since there is no brazing material layer on the outer surface of the heat exchanger tube 4, there is no erosion action on the outer surface of the core 30 of the heat exchanger tube 4 even if the brazing material is fluidized by heating. The corrosion resistance of the exchanger tube 4 can be relatively improved. Further, since the sheet-like member A pre-coated with the flux is used for forming the heat exchanger tube 4, the step of applying the flux during the forming of the heat exchanger tube 4 by roll homing is not required, and the heat exchanger tube 4 can be simplified. And since a flux layer is not formed in the outer fin 5, the process itself which precoats a flux can be deleted.

  On the other hand, as shown in FIG. 6, the brazing filler metal layer is not formed on the surface of the core material 34 and the flux layer 36 is formed as shown in FIG. In the heat exchanger tube 4, the brazing filler metal layer 34 is formed on the outer surface of the core member 30, while the flux layer may not be provided.

  Even in this case, when the temporary assembly of the heat exchanger is heated, the brazing material on the outer surface of the heat exchanger tube 4 is fluidized, and the brazing material is supplied also to the outer fin 5 side. The oxide film on the outer surfaces of the fins 5 and the heat exchanger tubes 4 is removed by supplying the flux between the surfaces of the outer fins 5 by heating and supplying between the outer fins 5 and the heat exchanger tubes 4. For this reason, it is possible to perform the brazing of the outer fin 5 and the heat exchanger tube 4 satisfactorily in a minimum amount without producing an excessive brazing material or flux.

  As shown in FIG. 7, even in the relationship between the heat exchanger tubes 4 and the inner fins 15, no brazing material layer is formed on the inner surface of the core material 37 for the inner fins 15. In the heat exchanger tube 4, the brazing filler metal layer 33 is formed on the inner surface of the tube 30 with respect to the core material 30, but the flux layer may not be provided.

  Even in this case, when the temporary assembly of the heat exchanger is heated, the brazing material on the inner surface of the heat exchanger tube 4 is fluidized, and the brazing material is supplied also to the inner fin 15 side. The oxide film on the inner surfaces of the fins 15 and the heat exchanger tubes 4 is removed by supplying the flux between the surfaces of the inner fins 15 by heating and supplying them between the inner fins 15 and the heat exchanger tubes 4. For this reason, it is possible to perform the brazing of the inner fin 15 and the heat exchanger tube 4 satisfactorily in a minimum amount without producing an excessive brazing material or flux.

Fig.1 (a) is a front view which shows the whole structure of an example of the heat exchanger with which this invention is used, FIG.1 (b) is a side view of the heat exchanger. Fig.2 (a) is a top view of the upper tank of a heat exchanger same as the above, and FIG.2 (b) is a bottom view of the lower tank of the same heat exchanger. Fig.3 (a) is explanatory drawing which shows the arrangement configuration of the heat exchanger tube and outer fin which comprise the core component of the heat exchanger same as the above, FIG.3 (b) is sectional drawing of a tank same as the above. is there. FIG. 4A is an explanatory view showing the arrangement of the heat exchange tubes and inner fins that constitute the core components of the above heat exchanger, and FIG. 4B shows the configuration of the inner fins of the above. It is explanatory drawing shown. FIG. 5 is an explanatory view showing a first embodiment in which a flux layer is formed on a heat exchanger tube and a brazing filler metal layer is formed on an outer fin. FIG. 6 is an explanatory view showing a second embodiment in which a brazing filler metal layer is formed on the heat exchanger tube and a flux layer is formed on the outer fin. FIG. 7 is an explanatory view showing a third embodiment in which a brazing filler metal layer is formed on a heat exchanger tube and a brazing filler metal layer is formed on an inner fin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 4 Heat exchanger tube 5 Outer fin 15 Inner fin 30 Tube core material 31 Tube flux layer 32 Tube sacrificial corrosion layer 33 Tube brazing material layer 34 Outer fin core material 35 Outer fin brazing material layer 36 Flux layer of outer fin 37 Core material of inner fin 38 Flux layer of inner fin A Sheet-like member B Sheet-like member C Sheet-like member

Claims (6)

A component in which a brazing filler metal layer is formed and a component in which the brazing filler metal layer is not supplied with the brazing filler metal supplied from the component in which the brazing filler metal layer is formed,
A core part of a heat exchanger, wherein a part on which the brazing material layer is not formed is provided with a flux on the surface by a coating process at a material stage. A heat exchange tube in which no brazing material layer is formed, and an outer fin in which a brazing material layer is disposed alternately with the heat exchanger tube,
The heat exchanger tube is characterized in that a flux is applied to one or both surfaces in contact with the outer fin by a coating process at a material stage. A roll homing tube in which a brazing filler metal layer is not formed and outer fins in which a brazing filler metal arranged alternately with the roll homing tube is formed, and a flux is pre-coated on the outer surface of the roll homing tube. The core part of the heat exchanger. A heat exchange tube having a brazing filler metal layer formed on the outer surface, and an outer fin in which a brazing filler metal layer alternately disposed with the heat exchanger tube is not formed,
The outer fin has a core portion of a heat exchanger in which a flux is applied to a surface in contact with the heat exchanger tube by a coating process at a material stage. A heat exchanger tube having a brazing filler metal layer formed on a side surface of the heat exchange medium passage, and an inner fin inserted into the heat exchange medium passage of the heat exchanger tube,
The inner fin has a core portion of a heat exchanger in which a flux is applied to a surface in contact with the heat exchanger tube by a coating process at a material stage. A core portion of a heat exchanger, comprising a roll homing tube having an inner fin, wherein a flux is precoated on an inner surface of the inner fin or the roll homing tube.

Images