JPH10206077A - Heat-exchanger made of aluminum alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure brazing ability between a plate piece and a header without welding the opening of a notch. SOLUTION: The melt point of a fist brazing material 20 laminated on the outer peripheral surface of a header 13 is reduced to a value lower than the melt point of a second brazing material 19 laminated on the two surfaces of a plate piece 9. Before viscosity of the second brazing material 19 is lowered, the first brazing material 20 is attracted to a microgap part and removed from the periphery of a notch 8. Thus, the second brazing material 19 is attracted to the first brazing material 20 and prevented from washing out to the outside of the header 13. As a result, the second brazing material 19 is effectively used for brazing 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 side header 4 is connected to each other by a plurality of heat transfer tubes 5, 5, and corrugated 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 inlet pipe 1
When the fluid flows through a number of heat transfer tubes 5 from the inlet header 2 toward the outlet header 4, the fluid is taken out from the outlet tube 3. , 6 with the air flowing around.

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. 2, one partition wall 7 is fixed to each of the inside of the entrance header 2 and the inside of the exit 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. Or 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 exactly half the 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. 2, the above-mentioned portions are brazed.

More specifically, as shown in FIG. 5, the header 13 which is the above-mentioned entrance-side header 2 or exit-side header 4 (FIGS. 2 to 4) 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 is connected to 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. 2).
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.
When the header 13 and the plate 9 formed by laminating 5, 17 are combined and heated 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.

By the way, the header 13 and the plate piece 9 are
Even if heating is performed simply in the combined state as shown in FIG. 5, the brazing between the header 13 and the plate piece 9 tends to be poor. The reason for this is that a part of the brazing material 17, 17 laminated on both surfaces of the plate piece 9 is pulled by the brazing material 15 laminated on the outer peripheral surface of the header 13 and comes out of the header 13. is there. 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 the heat brazing operation of the aluminum heat exchanger as shown in FIG. 2, the molten brazing materials 15, 17 are connected to the ends of the plurality of heat transfer tubes 5, 5 and the header 13 (the inlet side header). It gathers in a small gap existing in a fitting portion between a plurality of through holes formed in 2 or the outlet side header 4) and a fitting portion 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 5 and the plurality of through holes formed in the header 13 is large, the header 13 and the plate 9 become Insufficient brazing material is present at the fitting portion of That is, since 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 in contact with each other, the molten brazing materials 15, 17 are mixed with each other. All these brazing materials 15 and 17 tend to concentrate on a portion having a large suction force based on capillary action. As a result, there is a shortage of brazing material in the fitting portion between the header 13 and the plate piece 9, and the brazing property of the fitting portion between the header 13 and the plate piece 9 may be 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 welding 18 in order to insert the wire, 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 interrupted by welding 18 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.

[0010]

However, the header 13
In order to secure the brazing property of the fitting portion between the metal plate and the plate piece 9, the work of applying the welding 18 to the opening of the cutout 8 of the header 13 is troublesome, and is different from the equipment for brazing. Therefore, it is necessary to provide equipment for the heat treatment, which causes an increase in the manufacturing cost of the aluminum heat exchanger. In view of such circumstances, the present invention has been invented to realize a structure in which the brazing material existing between the header 13 and the plate piece 9 is not pulled out of the header 13 even when the welding is omitted. Things.

[0011]

An aluminum alloy heat exchanger according to the present invention comprises a pair of headers each made of an aluminum alloy and both ends, similarly to the above-mentioned conventional aluminum heat exchanger. A plurality of aluminum alloy heat transfer tube-equivalent members having the parts communicated in both headers, an aluminum alloy fin sandwiched between adjacent heat transfer tube-equivalent members, and provided at an intermediate portion of at least one of the headers And a partition made of an aluminum alloy that divides the inside of the header into a plurality of chambers. The header provided with the partition walls is formed by laminating a brazing material on the outer peripheral surface of a core material, and the plate piece for forming the partition walls is formed by laminating a brazing material on both surfaces of the core material. Inserts the plate piece into the header through a cutout formed in the header, and inserts the cutout between the portion of the outer peripheral edge of the plate piece deviated from the cutout and the inner peripheral surface of the header, and the cutout. The inner peripheral edge of the notch and a portion of the surface of the plate piece facing the inner peripheral edge are brazed.

In particular, in the heat exchanger made of aluminum alloy of the present invention, the melting temperature of the first brazing material laminated on the outer peripheral surface of the core material constituting the header is determined by adjusting the melting temperature of the core material constituting the plate piece. The melting temperature of the second brazing material laminated on both sides of the first brazing material is lower than that of the second brazing material, so that the first brazing material flows away from the periphery of the notch before the second brazing material is melted.

[0013]

In the case of the aluminum heat exchanger of the present invention configured as described above, the first brazing material and the second brazing material are:
Neither of these two brazing materials contacts in a molten state. That is, when the constituent members are heated for brazing, first, the first brazing material laminated on the outer peripheral surface of the header is melted, and the inner peripheral edge of the plurality of through holes formed in the header and the plurality of conductors are melted. It gathers on the parts to be brazed together, such as the outer peripheral surface of the end of the heat tube. In this way, the first brazing material laminated on the outer peripheral surface of the header was inserted before the second brazing material laminated on both surfaces of the plate for forming the partition wall was melted. It flows away from the peripheral edge of the notch toward the part to be brazed. Therefore, in a state where the temperature of each of the constituent members is further increased and the second brazing material is molten, the second brazing material does not come into contact with the first brazing material. As a result,
This second brazing material is effectively used for brazing a contact portion between the plate piece and the header without flowing out of the notch.

[0014]

FIG. 1 shows a first embodiment of the present invention.
An example is shown. The feature of the present invention is that the second brazing material 19, 19 laminated on both sides of the plate 9 is used for brazing the plate 9 and the header 13 for forming the partition wall 7.
The structure is for preventing the first brazing material 20 laminated on the outer peripheral surface of the header 13 from being pulled out and flowing out of the header 13. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIGS. 2 to 4 described above, overlapping illustration and description of the equivalent parts are omitted or simplified, and the following description will focus on the characteristic parts of the present invention. explain.

In the case of the aluminum alloy heat exchanger of the present invention, the melting temperature (melting point) of the first brazing material 20 laminated on the outer peripheral surface of the core material 14 constituting the header 13 is described.
Is lower than the melting temperature of the second brazing materials 19, 19 laminated on both sides of the core material 16 constituting the plate piece 9.
For this reason, the content of Si in the aluminum alloy as the first brazing material 20 is made relatively large (for example, about 7 to 8% by weight), and the content in the aluminum alloy as the second brazing material 19 is increased. Is relatively low (for example, 5.5 to 5.5).
6.5% by weight).

As described above, in the case of the aluminum heat exchanger of the present invention constituted by combining the first and second brazing materials 20 and 19 having different melting points from each other, the first brazing material 20 and the second brazing material 20 are combined. The two brazing materials 19, 19 do not come into contact with each other in a state where both of the brazing materials 20, 19 are molten. That is, in order to provide the partition 7 inside the header 13,
First, as shown in FIG. 1A, the plate piece 9 is inserted into the header 13 from the notch 8 formed in the header 13. The notch 8 is formed at the outer peripheral edge of the plate piece 9.
The portion deviated from the inner peripheral surface of the header 13 and the inner peripheral edge of the notch 8 and the portion of the surface of the plate piece 9 facing the inner peripheral edge are respectively abutted or minutely spaced. To face each other.

When the plate 9 and the header 13 are combined as described above, these members 9 and 13 are put into a heating furnace together with other components of the aluminum alloy heat exchanger, and Heat to a temperature (for example, about 600 to 640 ° C.). With the heating, the temperature of each of the above components gradually increases, and the first brazing material 20 and the second brazing material 1
9 and 19 melt. However, these two brazing materials 20, 1
9 is not melted at the same time, but first, the first brazing material 20 laminated on the outer peripheral surface of the core material 14 constituting the header 13 is melted. That is, since the first brazing material 20 is exposed on the outer peripheral surface of the header 13, it is strongly affected by the temperature in the heating furnace and rapidly rises in temperature.
It melts relatively quickly and its viscosity drops to the extent that it can flow freely.

A part of the first brazing material 20, which has been melted early and has a reduced viscosity, enters a minute gap between the inner peripheral edge of the notch 8 and the plate piece 9 as described above. As shown in FIG. 1 (B), a first fillet 21 is formed in a portion including the minute gap, and the remaining portion has inner peripheral edges of a plurality of through holes formed in the header 13 and a plurality of heat transfer tubes 5, 5 ( Gather at the parts to be brazed together, such as the outer peripheral surface of the end
A second fillet (not shown) is formed in the portion.
As a result, the first brazing material 20 laminated on the outer peripheral surface of the header 13 is melted before the second brazing materials 19, 19 laminated on both sides of the plate piece 9 for forming the partition wall 7 are melted. Except for the formation of one fillet 21, the plate piece 9 flows away from the peripheral edge of the notch 8 into which the plate piece 9 is to be brazed. Then, the first fillet 21
Between the first fillet and the second fillet.
Does not exist. That is, the second brazing material 1
As shown in FIG. 1 (B), while the melts 9 and 19 are not yet melted or the melt is still high in viscosity, as shown in FIG. In addition, except for the first fillet 21, the first brazing material 20
Will no longer exist.

As the temperature of the second brazing material 19 further increases, the viscosity of the second brazing material 19 decreases to such an extent that sufficient fluidity can be secured. And these second brazing materials 1
FIG. 1 (C) shows a state in which the outer peripheral edge of the plate piece 9 is separated from the notch 8 by the outer peripheral edge and the inner peripheral surface of the header 13.
A third fillet 22 is formed as shown in FIG. The third fillet 22 and the first fillet 21 solidify with a decrease in temperature, block the space between the plate piece 9 and the header 13, and partition the inside of the header 13 in an air-tight and liquid-tight manner. 7 is constituted.

In the case of the aluminum alloy heat exchanger of the present invention, the second brazing materials 19 and 19 are completely melted and the viscosity is sufficiently reduced to constitute the third fillet 22. In the state, each of these second brazing materials 19, 19
Does not contact the first brazing material 20. As a result, each of these second brazing materials 19, 19 is effectively used for brazing the contact portion between the plate piece 9 and the header 13.

The present inventor has determined that Si in the first brazing material 20
The content of Si in the second brazing material 19, 19 was 5.89%, and the content of
When the brazing of the plate piece 9 and the header 13 was performed by omitting (FIG. 6), it was confirmed that good brazing properties could be obtained. That is, according to the present invention, the same brazing property as when welding 18 is applied to the opening of the notch 8 using the same type of brazing material can be obtained.

[0022]

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.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention,
(A) shows a state before heating for brazing, (B) shows a state in which only the first brazing material is melted, and (C) shows a state in which the second brazing material is also melted to form a plate piece and a header. Sectional drawing of the partition formation part which each shows the brazed state.

FIG. 2 is a front view showing an example of an aluminum alloy heat exchanger to which the present invention is applied.

FIG. 3 is a perspective view showing a partition wall forming portion of the aluminum alloy heat exchanger shown in FIG. 2;

FIG. 4 is a cross-sectional view of the same partition wall forming portion.

FIG. 5 is a cross-sectional view of a partition forming portion, showing a more specific structure before heat brazing.

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.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inlet pipe 2 Inlet header 3 Outlet pipe 4 Outlet header 5 Heat transfer tube 6 Fin 7 Partition 8 Notch 9 Plate piece 10 Small diameter side semi-arc part 11 Large diameter side semi-arc part 12 Step part 13 Header 14 Core material 15 Brazing Material 16 core material 17 brazing material 18 welding 19 second brazing material 20 first brazing material 21 first fillet 22 third fillet

Claims (1)

[Claims] 1. A pair of headers each made of an aluminum alloy, a plurality of aluminum alloy heat transfer tube equivalent members having both ends passing through both headers, and adjacent heat transfer tube equivalent members. An aluminum alloy fin sandwiched between, and an aluminum alloy partition provided at an intermediate portion of at least one of the headers and dividing the inside of the header into a plurality of chambers, a header provided with the partition, The brazing material is laminated on the outer peripheral surface of the core material, the plate piece for forming the partition is a lamination of the brazing material on both surfaces of the core material, and the partition is formed by cutting out the notch formed in the header. Through the plate piece into the header, 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 between the inner peripheral edge of the notch and the plate piece. In an aluminum alloy heat exchanger formed by brazing a part of the surface with a portion facing the inner peripheral edge, the first brazing material laminated on the outer peripheral surface of the core material constituting the header is provided. The melting temperature is lower than the melting temperature of the second brazing material laminated on both sides of the core material constituting the plate piece, and the first brazing material is melted from the peripheral portion of the notch before the second brazing material is melted. An aluminum alloy heat exchanger characterized in that the brazing material is washed away.