JPH10225766A - Heat exchanger made of aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely braze without welding a gap between plate piece and header, to secure tightness by a partition, and to manufacture the heat exchanger with satisfactory function at a low cost by making a metal plate composing a pair of headers the monolayer material of an only core material, without laminating a brazing filler metal on both surfaces, an making the plate piece composting the partition a both surface clad material made by laminating the brazing filler metal on both surfaces of front and rear of the core material. SOLUTION: The brazing filler metals 17 laminated on both sides of the plate piece 9 composing the partition 7 do not come into contact with another brazing filler metal. That is, since the header 13 forming a notch 8 for inserting the plate piece 9 is composed of the monolayer material, in the surroundings of this notch 8, any brazing filler metal except the brazing filler metals 17 laminated on both surfaces of the plate piece 9, do not exist. Therefore, the brazing filler metal 17 laminated on the plate piece 9 side is not drawn by the brazing filler metal 15 laminated on the header 13 side. The brazing filler metal 17 laminated on this plate piece 9 does not flow out outside the notch 8, and the brazing filler metal 17 is effectively used for brazing a contact part between the plate piece 9 and the header 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an aluminum alloy heat exchanger used as a condenser or the like constituting an air conditioner for an automobile, and invented in order to effectively prevent performance deterioration due to poor brazing. Things.

[0002]

2. Description of the Related Art As a heat exchanger used as a condenser of a vehicle air conditioner, for example, Japanese Utility Model Application Laid-Open No. 64-8081 discloses an aluminum alloy heat exchanger having a structure as shown in FIG. . In this conventional aluminum alloy heat exchanger, an aluminum alloy inlet header 2 having an inlet pipe 1 connected to an upper end face thereof, and an inlet pipe 2 disposed parallel to the inlet header 2 and an outlet pipe 3 connected to a lower end face thereof. The outlet header 4 is connected to each other by a plurality of heat transfer tubes 5, 5, and corrugated outer fins 6, 6 are sandwiched between adjacent heat transfer tubes 5, 5. When heat exchange is performed between a fluid such as a refrigerant and air, the fluid is sent from the inlet pipe 1 and taken out from the outlet pipe 3.
While this fluid flows through a number of heat transfer tubes 5 from the inlet header 2 to the outlet header 4, these heat transfer tubes 5
Heat is exchanged between the outer fins 5 and the air flowing around the outer fins 6 and 6.

In the case of an aluminum alloy heat exchanger constructed and operated as described above, the flow path of a fluid such as a refrigerant flowing through the heat transfer tubes 5, 5 is lengthened to increase the flow rate of the fluid. In order to improve the performance of the heat exchanger, partition walls 7 are provided at an intermediate portion between the headers 2 and 4. For example, in the case of the structure shown in FIG. 1, one partition wall 7 is fixed to each of the inside of the entrance-side header 2 and the inside of the exit-side header 4. For this reason, the fluid such as the refrigerant sent from the inlet pipe 1 to the inlet header 2 is first sent to the outlet header 4 through some of the heat transfer tubes 5, 5. Then, the fluid is returned from the outlet header 4 to the inlet header 2 again through another heat transfer tube 5, 5 and further sent to the outlet header 4 through the remaining heat transfer tubes 5, 5. Sent from 3

As described above, the partition 7 for dividing the inside of the entrance header 2 or the exit header 4 into a plurality of chambers is provided, for example, as shown in FIGS. Is mounted on the outlet side header 4. The same applies hereinafter.) That is, a slit-shaped notch 8 is formed on the side surface of the entrance-side header 2 over just a half circumference of the entrance-side header 2.
The plate piece 9 constituting the partition wall 7 has a small-diameter side semicircular arc portion 10 having an outer peripheral edge coinciding with the inner peripheral surface of the entrance side header 2 and a large diameter having an outer peripheral edge almost coincident with the outer peripheral surface of the entrance side header 2. Steps 12 and 12 are formed in a continuous portion between the two semicircular arc portions 10 and 11.

[0005] The plate piece 9 formed in this manner is inserted into the notch 8 from the side of the small diameter side semicircular arc portion 10.
Airtightness is provided between the outer peripheral edge of the small-diameter semicircular portion 10 and the inner peripheral surface of the inlet header 2 and between the inner peripheral edge of the notch 8 and the outer peripheral portion of the large-diameter semicircular portion 11. The partition walls 7 are formed by brazing in a liquid-tight manner. That is,
Since a brazing material layer is present on the surfaces of the plate piece 9 and the entrance header 2 each made of a so-called clad material formed by laminating a core material and a brazing material, heat exchange made of aluminum alloy is performed. If the components of the vessel are heated in a state of being temporarily assembled as shown in FIG. 1, the above-mentioned inter-parts are brazed.

[0006] More specifically, as shown in FIG. 4, the header 13, which is the entrance header 2 or the exit header 4 (FIGS. 1 to 3), has a brazing material 15 laminated on the outer peripheral surface of a core material 14. The plate piece 9 for forming the partition 7 is made of the core material 1.
6, brazing materials 17 and 17 are laminated on both surfaces. In addition, the brazing material 15 laminated on the outer peripheral surface of the core material 14 constituting the header 13 includes the inner peripheral edges of a plurality of through holes (not shown) formed in the header 13 and the heat transfer tubes 5, 5 (FIG. 1).
For brazing to the outer peripheral surface of the end portion. As described above, the brazing material 1 is provided on one or both sides of the cores 14 and 16.
If the header 13 and the plate 9 formed by laminating 5 and 17 are heated in a combined state as shown in FIG.
The brazing material 17, 17 laminated on both sides of the
Of the outer peripheral edge of the header 13
And between the inner peripheral edge of the notch 8 and a part of the surface of the plate piece 9 facing the inner peripheral edge.

On the other hand, as the heat transfer tubes 5, 5, the use of so-called combined tubes, as shown in FIG. The heat transfer tube 5 is formed by folding an intermediate portion in the width direction of a plate material made of an aluminum alloy into a U-shape, and forming a folded portion 18 and the folded portion 1.
8, a pair of parallel flat plate portions 1 continuous from both end edges
9 and 19 are provided. And these two flat plate portions 19,
The bent portions 20 and 20 are respectively provided at the tip edges of the 19
Formed in a direction approaching each other, these bent portions 20,
20 are overlapped with each other. The overlapping portions of the distal ends of the two bent portions 20 and 20 are brazed and joined together with other components at the same time.

An inner fin 21 is inserted inside the heat transfer tube 5 and the inner fin 21 is brazed to the inner surface of each of the flat plates 19.
The inner fins 21 disturb the flow of the fluid (refrigerant) flowing in the heat transfer tube 5, improve the heat exchange efficiency between the fluid and the heat transfer tube 5, and form a pair of the heat transfer tube 5. The distance between the flat plate portions 19 and 19 is prevented from being widened, and the pressure resistance of the heat transfer tube 5 is improved. The inner fin 21 is formed by bending a band-shaped aluminum alloy plate.

In order to integrally braze and join the constituent members of the aluminum alloy heat exchanger as described above, each constituent member is a clad material in which a brazing material is laminated on both surfaces or one surface thereof. First, the plate members forming the headers 2 and 4 on the inlet side and the outlet side are each a core material (JIS A 3003).
A brazing material (aluminum alloy having a high Si content and a relatively low melting point, such as JIS A 4045 material) is laminated on one surface of a material such as an aluminum alloy having a required strength and a relatively high melting point. With the so-called single-sided clad material, and with the headers 2 and 4 configured, the brazing material is
Is located on the outer peripheral surface. The plate material constituting each of the heat transfer tubes 5 is a so-called single-sided clad material in which a brazing material is laminated on one surface of a core material. Surface. The inner fin 21 is a double-sided clad material in which a brazing material is laminated on both sides of a core material. Each of the plate members forming the outer fins 6 is a single-layer member made of only a core material without laminating a brazing material on both surfaces.
Further, the plate piece 9 constituting the partition wall 7 is a double-sided clad material in which a brazing material is laminated on both front and back surfaces of a core material.

[0010]

The header 13
Even if the plate 13 and the plate 9 are heated in a state of being simply combined as shown in FIG. 4, the brazing between the header 13 and the plate 9 tends to be poor. The reason is that a part of the brazing material 17, 17 laminated on both sides of the plate piece 9
This is because it is pulled by the brazing material 15 laminated on the outer peripheral surface of No. 3 and comes out of the header 13. That is, the brazing materials 15, 17 melted by the heating tend to gather in the minute gaps due to the capillary phenomenon. Specifically, at the time of heating brazing of an aluminum heat exchanger as shown in FIG.
The melted brazing materials 15, 17 are connected to a plurality of heat transfer tubes 5, 5,
At the end of the header 13 and the plurality of through-holes formed in the header 13 (the entrance header 2 or the exit header 4), and the minute gaps existing in the engagement between the header 13 and the plate piece 9. .

At this time, if the suction force for drawing the brazing material into the fitting portion between the end portions of the plurality of heat transfer tubes 5 and the plurality of through holes formed in the header 13 is large, the header 13 and the plate 9 Insufficient brazing material is present at the fitting portion with the wire. That is, header 1
Since the brazing material 15 laminated on the outer peripheral surface of 3 and the brazing materials 17 laminated on both sides of the plate piece 9 are in contact with each other, in a state where the molten brazing materials 15 and 17 are mixed with each other,
All of these brazing materials 15 and 17 tend to concentrate on a portion where the suction force due to the capillary phenomenon is large. As a result,
There is a possibility that the brazing material existing at the fitting portion between the header 13 and the plate piece 9 becomes insufficient, and the brazing property of the fitting portion between the header 13 and the plate piece 9 becomes poor. In particular, even if the brazing property between the inner peripheral surface of the header 13 and the outer peripheral edge of the plate piece 9 becomes poor, it cannot be confirmed from the outside. In addition, if a fluid such as a refrigerant leaks at the defective brazing portion, the aluminum heat exchanger such as a condenser does not exhibit the expected performance.

For this reason, conventionally, as shown in FIG.
After the opening of the notch 8 formed in the header 13 is closed by the welding 23 in order to insert the solder, heating for brazing is performed. As described above, if the brazing material 15 laminated on the outer peripheral surface of the header 13 and the brazing materials 17, 17 laminated on both surfaces of the plate piece 9 are cut off by welding 23 and then heating for brazing is performed, Insufficient brazing material present at the fitting portion between the header 13 and the plate piece 9 prevents the
The brazing property of the fitting portion between the plate 3 and the plate piece 9 can be ensured. However, in order to secure the brazing property of the fitting portion between the header 13 and the plate piece 9, the work of applying the welding 23 to the opening of the cutout 8 of the header 13 as described above is troublesome, and furthermore, the brazing operation is difficult. Equipment for welding, which is different from the equipment for
This causes an increase in the manufacturing cost of the aluminum heat exchanger.

Also, depending on the brazing conditions, damage similar to corrosion, which is called so-called erosion, may occur on a part of the inner surfaces of the bent portions 20 constituting the heat transfer tubes 5. is there. The mechanism by which such damage occurs is
It is as follows. Since there is a minute gap in the butted portion 20, butted portion 20, when the brazing material laminated on the front and back surfaces of both the header 2 and 4 on the inlet side and the outlet side is melted by heating for brazing. Then, the brazing material enters the minute gap due to the capillary phenomenon, and forms a solder pool 22 at the abutting portion as shown in FIG. When Si in the brazing material forming such a brazing pool 22 enters the aluminum alloy forming the core material forming the heat transfer tube 5 and forms a new alloy in the vicinity of the brazing pool 22, Melting point of the aluminum alloy becomes low. In this state, when the molten brazing material flows through the minute gap in the axial direction of the heat transfer tube 5 and removes the brazing material in the portion of the brazing pool 22, the thickness of the portion becomes thin.

That is, in the case of the conventional structure, since the brazing material is not originally present on the inner peripheral surface of each of the heat transfer tubes 5, 5, the amount of the brazing material present on the inner peripheral surface side is not necessarily large. Therefore, even when the brazing pool 22 as shown in FIG. 7 is formed once, the brazing material in the brazing pool 22 may have a melting point depending on the brazing conditions such as the attitude of the aluminum alloy heat exchanger during brazing. Along with some of the core material melted by lowering,
May be taken away by other parts. If the thickness of the core material constituting each of the heat transfer tubes 5, 5 is reduced in this manner, the durability of the aluminum alloy heat transfer tube is impaired, which is not preferable.

Further, both the headers 2 and 4 on the entrance side and the exit side are provided.
Is made of a single-sided clad material in which a brazing material is laminated on one side of a core material, so that the cost of both the headers 2 and 4 increases. That is, if the headers 2 and 4 are made of extruded pipes, the cost can be reduced. However, since the brazing material cannot be laminated on the extruded pipes, in the case of the conventional structure, the extruded pipes are attached to the headers 2 and 4. Can not be adopted.

In view of such circumstances, according to the present invention, even if welding is omitted, the brazing material existing between the header 13 and the plate piece 9 is not pulled out of the header 13 and the heat transfer tube The present invention has been made to realize a structure in which no damage is generated at the joint of the fifth and fifth parts, and an inexpensive extrusion tube can be used for the header 13.

[0017]

An aluminum alloy heat exchanger according to the present invention has a pair of headers each made of an aluminum alloy and an aluminum alloy heat exchanger, similarly to the above-mentioned conventional aluminum heat exchanger. The widthwise intermediate portion of the alloy plate is folded back into a U-shape, and the ends of the bent portions formed at both end edges of the plate are overlapped with each other and brazed to each other. A plurality of aluminum alloy heat transfer tubes which are connected to the inside of each of these headers through through holes formed in both headers, and brazed to the inner peripheral edge of each of the through holes and the outer peripheral surfaces of both ends thereof; Between the inner heat transfer tubes adjacent to each other and the aluminum alloy inner fins, which are inserted inside the An outer fin made of aluminum alloy which is sandwiched and abutted with each of these heat transfer tubes and an aluminum alloy outer fin provided at an intermediate portion of at least one of the headers and dividing the inside of the header into a plurality of chambers. And a partition. And this partition inserts a plate piece into this header through the notch formed in the header, and between the part outside the notch at the outer peripheral edge of the plate piece and the inner peripheral surface of the header, In addition, brazing is performed between the inner peripheral edge of the notch and a part of the surface of the plate piece facing the inner peripheral edge.

In particular, in the aluminum alloy heat exchanger of the present invention, each of the plate members constituting the pair of headers is a single layer made of only a core material without laminating brazing material on any of both surfaces. Material. The plate material constituting each of the heat transfer tubes is a double-sided clad material in which a brazing material is laminated on both front and back surfaces of a core material. The plate material constituting the outer fin is a single-layer material composed of only a core material without laminating a brazing material on both sides. Further, a plate piece constituting the partition is a double-sided clad material in which a brazing material is laminated on both front and back surfaces of a core material. The plate material constituting the inner fin may be any of a single-layer material, a single-sided clad material, and a double-sided clad material.

[0019]

In the case of the heat exchanger made of aluminum of the present invention having the above-described structure, the brazing material laminated on both sides of the plate constituting the partition does not come into contact with other brazing materials. That is, since the header formed with the notch for inserting the plate piece is made of a single-layer material, around the notch, there is no brazing material other than the brazing material laminated on both sides of the plate piece. not exist. Therefore, as in the conventional structure described above, the brazing material laminated on the plate piece is not drawn by the brazing material laminated on the header side, and the brazing material laminated on the plate piece is
It is effectively used for brazing a contact portion between the plate piece and the header without flowing out of the notch.

Further, the plate material constituting the heat transfer tube is laminated with a brazing material not only on the surface on the outer peripheral surface side of the heat transfer tube but also on the surface on the inner peripheral surface side. Therefore, the brazing material melts,
Even if a solder pool is formed at the joint of the heat transfer tubes, the brazing material forming the flash pool does not flow to other portions. That is, since a sufficient amount of brazing material can be secured on the inner peripheral surface side of the heat transfer tube, a substantially uniform braze (fillet) is formed in the joining portion over the entire length of the heat transfer tube, and solidified as it is. I do. Therefore, the combined thickness of the heat transfer tubes does not partially decrease.

Further, since the header is made of a single layer material,
This header can be made with an inexpensive extruded tube. Therefore, the cost of the aluminum alloy heat exchanger can be reduced based on the reduction of the material cost of the header.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The feature of the present invention resides in that, in order to integrally braze the constituent members, the lamination portion of the brazing material laminated on a part of the constituent members is regulated. Regarding the specific shape and combination of the constituent members, for example, aluminum alloy heat exchangers of various structures conventionally known, such as aluminum alloy heat exchangers as shown in FIGS. Can be implemented in a vessel. Examples of the aluminum alloy used as the core material include JIS A 3003,
As the aluminum alloy used as the brazing material, for example, a conventionally used aluminum alloy such as JIS A 4343, 4045 or the like can be appropriately selected and used according to the required strength, corrosion resistance and the like. Therefore, the technology for carrying out the present invention includes "means for solving the problem" and "action".
Are fully disclosed.

[0023]

Since the aluminum alloy heat exchanger of the present invention is constructed and operates as described above, the plate piece and the header can be securely connected without welding between the plate piece and the header. By brazing, it is possible to ensure the sealing performance of the partition wall constituted by the plate pieces. Therefore, a high-performance aluminum alloy heat exchanger can be manufactured at low cost. Further, regardless of the brazing conditions, the thickness of the heat transfer tube is prevented from being partially reduced, and the reliability and durability of the obtained aluminum alloy heat exchanger can be improved. Further, the cost can be reduced by adopting an inexpensive extrusion tube as the header.

[Brief description of the drawings]

FIG. 1 is a front view showing an example of an aluminum alloy heat exchanger to which the present invention is applied.

FIG. 2 is a perspective view showing a partition wall forming portion in the aluminum alloy heat exchanger shown in FIG.

FIG. 3 is a cross-sectional view of a partition forming portion.

FIG. 4 is a cross-sectional view of a partition forming portion, showing a more specific structure of the related art before heating brazing.

FIG. 5 is an end perspective view of a heat transfer tube provided with inner fins.

FIG. 6 is a cross-sectional view of a partition wall forming portion, showing a state in which a plate piece and a header are welded to ensure brazing properties.

FIG. 7 shows a state of a brazing pool generated during brazing.
Partial sectional view of a heat transfer tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet pipe 2 Inlet header 3 Outlet pipe 4 Outlet header 5 Heat transfer tube 6 Outer fin 7 Partition wall 8 Notch 9 Plate piece 10 Small diameter semicircular arc part 11 Large diameter semicircular arc part 12 Step 13 Header 14 Core material 15 Brazing material 16 core material 17 brazing material 18 folded portion 19 flat plate portion 20 bent portion 21 inner fin 22 solder pool 23 welding

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F28F 9/26 F28F 9/26

Claims (1)

[Claims] 1. A pair of headers, each made of an aluminum alloy, and a middle portion in the width direction of a plate made of an aluminum alloy, each of which is folded back into a U-shape, and bent portions formed at both end edges of the plate. The tips are overlapped with each other and brazed to each other, and both ends are passed through the respective headers through the through holes formed in the both headers, and the inner peripheral edge of each of the through holes and the respective both ends are formed. A plurality of aluminum alloy heat transfer tubes brazed to the outer peripheral surface, and an aluminum alloy inner wire inserted inside each of the heat transfer tubes and brazed at the contact portions with the inner surface of each of the heat transfer tubes. An aluminum alloy outer fin sandwiched between adjacent fins and adjacent heat transfer tubes, and abutting portions of these heat transfer tubes are brazed together. And a partition made of an aluminum alloy which is provided at an intermediate portion of one of the headers and divides the inside of the header into a plurality of chambers. The partition inserts a plate piece into the header through a cutout formed in the header. At the same time, between the portion of the outer peripheral edge of the plate piece deviated from the notch and the inner peripheral surface of the header, and the inner peripheral edge of the notch and a part of the surface of the plate piece oppose the inner peripheral edge. In a heat exchanger made of aluminum alloy formed by brazing with a portion to be formed, each of the plate members constituting the pair of headers is constituted by only the core material without laminating the brazing material on any of both surfaces. The plate material constituting each heat transfer tube is a double-sided clad material in which a brazing material is laminated on both sides of the core material, and the plate material constituting the outer fin is a brazing material laminated on both surfaces. Without the core material A single-layer material,
A heat exchanger made of an aluminum alloy, wherein a plate piece constituting the partition is a double-sided clad material in which a brazing material is laminated on both front and back surfaces of a core material.