JP2006320935A - Method for manufacturing heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a heat exchanger capable of reasonably brazing tubes of the heat exchanger. <P>SOLUTION: In the method for manufacturing a heat exchanger having a core 10 with tubes 20 and fins 30 layered thereon and a tank body 40 with an end of the tube connected thereto, and capable of performing the heat exchange by the heat of a medium flowing in the tubes, transferred to the core, a plurality of kinds of components are assembled and subjected to the in-furnace brazing. The tubes are provided by brazing the components formed of a strip-like material in the in-furnace brazing. During the in-furnace brazing, by heating a component having the heat capacity larger than that of the tube component in advance during the in-furnace brazing, the difference between the time at which the tube component reaches the brazing temperature, and the time at which the component having the larger heat capacity reaches the brazing temperature is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention includes a core formed by stacking tubes and fins, and a tank body connected to the ends of the tubes, and a heat exchanger manufacturing method for exchanging heat by heat transmitted to the core through a medium flowing through the tubes About.

  Heat exchangers such as automobile radiators, condensers and evaporators in refrigeration cycles have a core formed by alternately laminating flat tubes and corrugated fins, and a tank body to which the ends of the tubes are connected. Provided, and heat exchange of the medium is performed by heat transmitted to the tube and the fin. The medium is taken into the inside from an inlet portion provided in the tank body, passes through the tube while exchanging heat by heat transmitted through the core, and then discharged to the outside from an outlet portion provided in the tank body.

Such a heat exchanger is manufactured by assembling components such as tubes, fins, and a tank body, and brazing the assembled body in a furnace. As a tube, there is also known a tube formed by roll-forming a band-shaped aluminum alloy material clad with a brazing material into a predetermined shape and brazing it by brazing in a furnace. Patent Documents 1 and 2 disclose the configuration of a strip-shaped material that is brazed in a furnace.
Japanese Patent Laid-Open No. 5-65582 JP-A-5-230576

  In recent years, heat exchanger tubes have tended to be miniaturized and refined to improve the performance of heat exchangers, and the brazing in the furnace described above sufficiently improves the performance, corrosion resistance, and manufacturability of the tubes. It is necessary to consider this.

  For example, a brazing material layer is provided on the tube material, and Si contained in the brazing material layer diffuses into the core material by brazing heating in the furnace. In addition, the tube material may be provided with a Zn-containing layer, and the Zn diffuses into the core material by heating in the furnace. The Si diffusion layer has a characteristic that erosion progresses along the grain boundary. When Si diffuses in the thickness direction of the material, erosion progresses in the thickness direction of the material due to grain boundary corrosion. On the other hand, the Zn diffusion layer has surface corrosion characteristics, and reduces the progress of erosion in the thickness direction due to the potential difference with the core material. When the Al-Si layer and the Al-Zn alloy layer clad on the respective surfaces of the material are heated, the Si diffusion layer and the Zn diffusion layer formed in the plate thickness direction are brought into contact with each other. When the corrosion that has progressed through the Zn diffusion layer reaches the Si diffusion layer, the corrosion rate in the thickness direction is accelerated, and the anticorrosion effect is extremely reduced. Since diffusion of Si and Zn proceeds according to the time when the constituent members of the tube formed from the material reach the brazing temperature, it is necessary to set the time appropriately in brazing in the furnace. .

  However, some heat exchanger components have a larger heat capacity than tube components. It is a structural member of a tank body. For this reason, the time when the constituent members of the tube reach the brazing temperature is unnecessarily long because the entire heat exchanger needs to be brazed. In order to secure a non-diffusion layer in which Si and Zn are not diffused, the core material has to be thick, which is a cause of hindering further miniaturization and refinement of the tube.

  This invention is made | formed in view of this situation, The objective is to braze the tube of a heat exchanger more rationally.

  The invention described in claim 1 of the present application includes a core formed by stacking tubes and fins, and a tank body connected to the ends of the tubes, and a medium flowing through the tubes is heated by heat transmitted to the cores. In the method of manufacturing a heat exchanger that performs heat exchange, the heat exchanger is formed by assembling a plurality of types of components and brazing them in a furnace, and the tube is formed from a strip-shaped material. The structural member is brazed by brazing in the furnace, and at the time of brazing in the furnace, the structural member having a heat capacity larger than that of the structural member of the tube is preliminarily heated, so that the tube The manufacturing method of the heat exchanger of the structure which reduces the difference of the time when the structural member of this reaches the brazing temperature and the time when the structural member with the said large heat capacity reaches the brazing temperature.

  The invention described in claim 2 of the present application is the method of manufacturing a heat exchanger according to claim 1, wherein a non-diffusion layer in which Si or Zn is not diffused is formed in the tube.

  According to the present invention, the tube of the heat exchanger can be brazed more rationally.

  Embodiments of the present invention will be described below with reference to the drawings. A heat exchanger 1 shown in FIG. 1 is a radiator of a refrigeration cycle for in-vehicle air conditioning that is mounted on an automobile. The heat exchanger 1 includes a core 10 in which flat tubes 20 and corrugated fins 30 are alternately stacked, and a pair of tank bodies 40 to which both longitudinal ends of the tubes 20 are connected. It is a thing. Reinforcing members 50 are provided on the upper and lower side portions of the core 10 in the stacking direction, and both end portions in the longitudinal direction of the reinforcing members 50 are respectively supported by the tank body 40. The tank body 40 is provided with a hole for inserting and connecting the ends of the tube 20 and the reinforcing member 50. In addition, an inlet 41 and an outlet 42 of a medium (that is, a refrigerant circulating in the refrigeration cycle) are provided at important points of the tank body 40, and the medium flowing from the inlet 41 is heated by the heat transmitted to the core 10. The tube 20 is circulated while being subjected to heat exchange, and flows out from the outlet 42.

  The constituent members of the heat exchanger 1, that is, the members constituting the tube 20, the fin 30, the tank body 40, and the reinforcing member 50 are each made of an aluminum alloy, and are assembled using a jig. It is brazed together by overheating in the furnace. In brazing in such a furnace, a brazing material and a flux are provided at the main points of each component. The inlet portion 41 and the outlet portion 42 may be brazed to the tank body 40 by in-furnace brazing, or may be welded to the tank body 40 after brazing in the furnace.

  FIG. 2 is an explanatory view showing a cross section of the tube 2 of this example. The tube 20 is formed by roll-forming a band-shaped material made of an aluminum alloy clad with a brazing material into a predetermined shape and brazing it by brazing in a furnace. The thickness of the material is 0.20 to 0.25 mm. The inside of the tube 20 is partitioned by a bead 21 formed by molding the material, and the top of the bead 21 is brazed to the inner surface of the tube 20. In the illustrated example, the tops of opposing beads 21 are brazed to each other. In roll forming, a bead 21 is provided at an important part of the material, and both end portions 22 and 23 in the width direction of the material are formed into a predetermined shape, the important part of the material is bent and folded into two, and the width of the material is determined. The direction end portions 22 and 23 are engaged with each other. That is, at one end in the width direction of the tube 20, an engagement portion 24 is provided that engages and brazes the width direction both ends 22 and 23 of the material. Further, a bent portion 25 formed by bending the material is provided at the other end portion in the width direction of the tube 20. A plurality of flow paths 26 partitioned by beads 21 are provided inside the tube 20.

  FIG. 3 is an explanatory view showing a cross-sectional structure of the material 100 of the tube 20. This material 100 is formed by providing a brazing material layer 120 on one surface of a core material 110 and a Zn-containing layer 130 on the other surface. The core material 110 is an Al—Mn alloy, the brazing filler metal layer 120 is an Al—Si alloy, and the Zn-containing layer 130 is an Al—Zn alloy or an Al—Si—Zn alloy. The thickness of the brazing filler metal layer 120 and the thickness of the Zn-containing layer 130 are each 16% or less of the total thickness. For example, a core material 110 having a thickness of 0.21 mm is clad with a brazing filler metal layer 120 having a thickness of 0.02 mm and a Zn-containing layer 130 having a thickness of 0.02 mm. In this case, the thickness of the brazing filler metal layer 120 and the thickness of the Zn-containing layer 130 with respect to the thickness of the material 100 are each 8 percent.

  According to brazing in the furnace, Si and Zn are diffused from the brazing material layer 120 and the Zn-containing layer 130, and diffusion layers 121 and 131 are formed. In this example, the structure described below prevents the diffusion layer 121 on the brazing filler metal layer 120 side and the diffusion layer 131 on the Zn-containing layer 130 side from intersecting. The core material 110 remains between the diffusion layers 121 and 131. That is, a non-diffusion layer in which Si or Zn is not diffused is formed. As a result, the corrosion resistance of the tube 20 is improved by the presence of the non-diffusion layer. The thickness of the non-diffusion layer is about 0.05 mm.

  FIG. 4 is a temperature characteristic graph in brazing in a furnace. (A) shows a conventional example, and (b) shows an example of the present invention. In this example, when brazing in the furnace, the structural member having a larger heat capacity than the structural member of the tube 20 is heated in advance, so that the time ta when the structural member of the tube 20 reaches the brazing temperature and the thermal capacity are large. The difference with the time tb when the constituent member reaches the brazing temperature is reduced. In the graph, the vertical axis T is temperature, and the horizontal axis t is time. The normal temperature is 25 degrees and the brazing temperature is 577 degrees. A solid line indicates a temperature change of the constituent member of the tube 20, and a chain line indicates a temperature change of the tank body 40 which is a constituent member having a larger heat capacity than the constituent member of the tube 20.

  According to the conventional example of FIG. 4A, in order to braze the heat exchanger 1 as a whole, the length of tb must be set to a predetermined length, and ta is unnecessary because of the heat capacity. become longer. This is because the temperature rise of the constituent members of the tube 20 is relatively fast.

  In this regard, according to the present example of FIG. 4B, since the constituent members of the tank body 40 having a larger heat capacity than the constituent members of the tube 20 are heated in advance, the difference between ta and tb is reduced. In the graph, ta and tb are substantially the same length. tc indicates the time during which the constituent members of the tank body 40 are heated. The heating method is not particularly limited, but in this example, a method is adopted in which a burner is installed on the side of the conveyor that conveys the assembly to the furnace, and the constituent members of the tank body 40 are locally heated by the burner. ing.

  According to such a structure, the brazing property of the tube 20 can be improved reliably. That is, when the brazing time is set according to a component having a large heat capacity, ta becomes unnecessarily long, and the material 100 of the tube 20 must be thickened to secure a non-diffusing layer. However, according to this example, since the difference between ta and tb is reduced by preheating the structural member having a large heat capacity, the length of ta can be set appropriately, and such inconvenience is avoided. be able to. Therefore, the tube 20 can be further miniaturized and refined.

  In addition, it is desirable that the jig used for brazing in the furnace has a small heat capacity. This is because if the heat capacity of the jig is large, the residual heat affects the length of ta. Therefore, in this example, the reduction of the heat capacity is achieved by adopting a hollow pipe as a jig part.

  As explained above, according to the manufacturing method of the heat exchanger of this example, the tube of the heat exchanger can be brazed more reasonably. It should be noted that the configuration in the present example can be appropriately changed in design within the technical scope described in the claims, and is of course not limited to the one described in the drawings.

  Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is an explanatory view showing a cross section of the tube 20 of this example. The tube 20 of this example is formed by roll-forming a band-shaped material so as to sandwich the second material that is the inner fin 27. The interior is partitioned by inner fins 27.

  FIG. 6 is an explanatory diagram showing a cross-sectional structure of the materials 100 and 200 of the tube 20. The material 100 constituting the outline of the tube 20 is formed by providing a Zn-containing layer 130 on one surface of the core material 110. The core material 110 is an Al—Mn alloy, and the Zn-containing layer 130 is an Al—Zn alloy or an Al—Si—Zn alloy. For example, a core material 110 having a thickness of 0.21 mm is clad with a Zn-containing layer 130 having a thickness of 0.02 mm. The second material 20 is formed by providing brazing material layers 220 on both surfaces of the core material 210. The core material 210 is an Al—Mn alloy, and the brazing material layer 220 is an Al—Si alloy. For example, a brazing material layer 220 having a thickness of 0.01 mm is clad on both surfaces of a core material 210 having a thickness of 0.09 mm. According to brazing in the furnace, Si and Zn are diffused from the brazing material layer 220 and the Zn-containing layer 130 to form diffusion layers 221 and 131. Other basic configurations are the same as those in the above-described embodiment.

  As described above, the configuration in which the component member having a larger heat capacity than the component member of the tube 20 is heated in advance can be applied to the tube 20 provided with the inner fins 27.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to manufacture favorably heat exchangers, such as a condenser of a refrigerating cycle, an evaporator, a radiator of a motor vehicle, and a heater core.

It is a front view which concerns on the Example of this invention and shows a heat exchanger. It is explanatory drawing which concerns on the Example of this invention and shows the cross section of a tube. It is explanatory drawing which concerns on the Example of this invention and shows the cross-section of the raw material of a tube. It is a temperature characteristic graph in the brazing in a furnace concerning the Example of this invention, Comprising: (a) shows a prior art example, (b) has shown the Example of this invention. It is explanatory drawing which concerns on the Example of this invention and shows the cross section of a tube. It is explanatory drawing which concerns on the Example of this invention and shows the cross-section of the raw material of a tube.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat exchanger 10 Core 20 Tube 21 Bead 22 End part 23 End part 24 Engagement part 25 Bending part 26 Flow path 27 Inner fin 30 Fin 40 Tank body 41 Inlet part 42 Outlet part 50 Reinforcement member 100 Tube material 110 Core material 120 Brazing material layer 121 Diffusion layer 130 Zn-containing layer 131 Diffusion layer 200 Second tube material 210 Core material 220 Brazing material layer 221 Diffusion layer

Claims (2)

In a method of manufacturing a heat exchanger, comprising: a core formed by stacking tubes and fins; and a tank body connected to an end of the tube, wherein a medium flowing through the tube exchanges heat with heat transmitted to the core. ,
The heat exchanger is formed by assembling a plurality of types of components and brazing them in a furnace,
The tube is formed by brazing a component formed by molding a strip-shaped material by brazing in the furnace,
At the time of brazing in the furnace, by heating in advance the structural member having a larger heat capacity than the structural member of the tube, the time for the structural member of the tube to reach the brazing temperature, and the structural member having the large heat capacity A method of manufacturing a heat exchanger, characterized by reducing a difference from a time when the brazing temperature is reached.   The method for manufacturing a heat exchanger according to claim 1, wherein a non-diffusion layer in which Si or Zn is not diffused is formed in the tube.

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