JPH11132688A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make compact a header tank by preventing the plate member of header tank in a heat exchanger from spreading after machining and reducing the overall thickness of the plate member of header tank. SOLUTION: When communicating header tanks 11, 12 are constructed by jointing a large number of juxtaposed flat tubes 14 at the opposite end parts thereof, an inside member 100 is constructed by bending a plate member, obtained by applying a skin brazing material to the surface of a core material, substantially tubularly. The inside member 100 is inserted with the end part of the flat tube 14 and provided with a hole for inserting a tube to be joined. An outside member for sustaining the substantially tubular tank shape of the inside member 100 is jointed integrally to the outer circumferential side of the inside member 100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for joining a plurality of flat tubes arranged in parallel to both ends of a flat tube to a header tank.
A heat exchanger that allows a heat exchange fluid to flow through a flat tube through a header tank, and particularly relates to improvement of a header tank portion, and is suitable for use as a condenser for condensing refrigerant in a vehicle air conditioner, for example. .

[0002]

2. Description of the Related Art A conventional heat exchanger of this type is disclosed, for example, in Japanese Patent Application Laid-Open No. 7-318287. In this prior art, an aluminum plate clad with a brazing material is bent into a cylindrical shape. At the same time, the header tank is formed into a cylindrical shape (pipe shape) by overlapping and brazing the bent ends of the plate material.

[0003] Both ends of the header tank in the longitudinal direction (axial direction) are closed by a cap member or an inlet / outlet joint for a fluid (refrigerant of a refrigeration cycle or the like).
Further, a long tube-shaped tube insertion hole is formed in the aluminum plate, and both ends of the flat tube are inserted into the tube insertion hole to integrally join the header tank and the flat tube.

[0004]

With such a structure, the overlapped portion of the bent end portion of the plate material easily spreads after bending due to the springback action of the plate material itself.
In some cases, it becomes difficult to insert the flat tube into the tube insertion hole of the plate material. Also, if the end of the tube insertion hole of the plate is opened to the bent end of the plate, the overlap of the bent end of the plate will be expanded after the heat exchanger is assembled and also when brazing. This is likely to cause problems such as falling off of the flat tube and poor sealing at the overlapped portion of the bent end portion of the plate material.

In Japanese Patent Application Laid-Open No. 3-260596, a notch is formed at a bent end of a plate material to form a tube insertion hole, and a flexible piece is formed at a side of the notch. On the other bent end portion opposite to the bent end portion having the flexible piece, a guide convex portion for bending the flexible piece toward the notch portion is formed. In the process of bending the plate into a cylindrical shape while the flat tube is inserted at the position of the notch, the flexible piece is bent toward the notch by the guide projection, and the flexible piece is placed on the flat tube surface. There has been proposed a pressure-contact type.

In the latter prior art, the flexible tube is bent toward the notch in the process of bending the plate into a cylindrical shape, and the flexible member is pressed against the surface of the flat tube so that the flat tube has a cylindrical shape. Securely fix to the plate material (header tank)
After the heat exchanger is assembled, problems such as falling off of the flat tube are prevented. However, according to the latter conventional technique, the flexible piece is bent and pressed against the flat tube surface as described above, so that the flat tube is deformed at the pressed portion, and the passage cross-sectional area of the flat tube is reduced, This may cause an increase in pressure loss of the fluid in the tube.

In view of the above, an object of the present invention is to reliably prevent the plate material of the header tank in the heat exchanger from expanding after bending without causing deformation of the flat tube. It is another object of the present invention to reduce the total thickness of the plate material of the header tank to reduce the size of the header tank.

[0008]

In order to achieve the above object, according to the first to fifth aspects of the present invention, both ends of a number of flat tubes (14) arranged in parallel are joined and communicate with each other. In constructing (11, 12),
Plate material (10) provided with a brazing material on the surface of the core material
1) is bent into a substantially cylindrical shape to form the inner member (1).
00), the inner member (100) is provided with tube insertion holes (102, 103) into which the ends of the flat tube (14) are inserted and joined, and the outer periphery of the inner member (100) is further provided. On the side, an outer member (110) for holding a substantially cylindrical tank shape of the inner member (100) is integrally joined.

According to this, the arrangement of the outer member (110) can surely prevent the inner member (100) from spreading after bending, so that the tube can be inserted into the tube insertion holes (102, 103) of the inner member (100). Insertion work is easy. In addition, the tube falls out of the tube insertion holes (102, 103) of the inner member (100), and the inner member (1
00) and the flat tube (14) can be prevented from being defective such as poor sealing.

Further, the outer member (110) disposed on the outer peripheral side of the inner member (100) allows the inner member (100) to be moved.
Is prevented, there is no danger that the flat tube is deformed and the pressure loss of the fluid in the tube is increased, unlike the conventional case where the flexible piece is pressed against the flat tube surface. In particular, as in the invention described in claim 2,
If the outer member (110) is made of a material having a smaller coefficient of thermal expansion than the inner member (100), the effect of preventing the inner member (100) from spreading can be maintained well even at a high temperature when brazing the heat exchanger. .

Further, if the outer member (110) is made of a material having a higher tensile strength than the inner member (100), the outer member (110) can be made of the header tank (11, 12). By utilizing as a strength member for ensuring the pressure resistance of (2), the total thickness of the header tank can be reduced as compared with the conventional structure, so that the header tank can be downsized and the heat exchanger can be downsized.

Further, if the outer member (110) is made of a material having a higher tensile strength per density than the inner member (100), the weight of the header tank can be reduced. And, as in the invention according to claim 5, the outer member (110) can be specifically made of an iron-based material, and the plate (101) constituting the inner member (100) is specifically made of It can be constituted by a plate material in which a skin material made of an aluminum brazing material is provided on a core material made of an aluminum-based material.

The reference numerals in parentheses attached to the respective means and the means described in the claims indicate the correspondence with the specific means described in the embodiments described later.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. (First Embodiment) FIG. 1 illustrates the entire structure of a condenser 10 in a vehicle air conditioner to which the present invention is applied. The condenser 10 is a compressor (not shown) in a refrigeration cycle of the vehicle air conditioner. ) Is to cool and condense the high-temperature and high-pressure superheated gas refrigerant discharged from the above). Also, as is well known, the condenser 10 is disposed at the forefront (in front of the engine cooling radiator) in the vehicle engine room, and cooling air (outside air) blown by a cooling fan common to the engine cooling radiator. Cooling.

The condenser 10 has a pair of header tanks, that is, first and second header tanks 11 and 12 arranged at a predetermined interval.
Reference numerals 1 and 12 each have a shape extending in a substantially cylindrical shape in the vertical direction. A core 13 for heat exchange is arranged between the first and second header tanks 11 and 12. Condenser 10 of this example
Is generally referred to as a multi-flow type, and the core portion 13 includes first and second header tanks 11 and 12.
A plurality of flat tubes 14 through which the refrigerant flows in the horizontal direction are arranged in parallel in the vertical direction.
And a corrugated fin 15 is interposed therebetween.
One end of the flat tube 14 communicates with the first header tank 11, and the other end communicates with the second header tank 12.

The flat tube 14 is a multi-hole flat tube in which a number of holes for refrigerant flow are formed in parallel, and is formed by extruding aluminum (for example, A1050). The corrugated fin 15 is made of a brazing material (for example, A4343) and a core material (for example, A3).
923) is formed by corrugating an aluminum-clad sheet material clad on the aluminum clad sheet.

A refrigerant inlet piping joint (refrigerant inlet) 16 is arranged and joined above the second header tank 12. A refrigerant outlet-side piping joint (refrigerant outlet) 17 is arranged and joined below the second header tank 12. Further, in the present example, one separator 18 is arranged in an intermediate portion between the inlet-side piping joint 16 and the outlet-side piping joint 17 in the second header tank 12, so that the second header tank 12 The inside is vertically divided into two spaces 12a and 12b. Also, the first and second header tanks 11, 12
The openings at both ends in the axial direction (longitudinal direction) are sealed by cap members 19 to 22, respectively.

With the above configuration, the refrigerant from the inlet side pipe joint 16 is supplied to the upper space 12 of the second header tank 12.
a, the refrigerant flows into the upper half flat tube 14 of the core portion 13, and then the refrigerant is U-turned in the first header tank 11 to flow into the lower half flat tube 14 of the core portion 13. The refrigerant flows to the outlet-side piping joint 17 through the lower space 12b of the two header tanks 12. During this time, the refrigerant exchanges heat with cooling air (outside air) passing through the core portion 13 through the flat tubes 14 and the corrugated fins 15 to be cooled and condensed.

Although not shown in FIG. 1, side plates each having a U-shaped cross section are arranged on both upper and lower sides of the heat exchange core portion 13, and the condenser 10 is connected through the side plates. It is designed to be mounted on the vehicle body. Next, the first and second header tanks 11, which are features of the present invention,
The specific structure of the first and second header tanks 11 and 12 is basically the same, and is bent into a substantially cylindrical shape as shown in FIG. It has an inner member 100 forming a hollow tank shape, and an outer member 110 arranged on the outer peripheral side of the substantially cylindrical tank shape of the inner member 100.

The outer member 110 is for maintaining the substantially cylindrical tank shape of the inner member 100. Therefore, the outer member 110 has a shape in which a part of the circumferential surface of the cylinder is cut off (an arc-shaped cross section). ) And integrally joined to the outer peripheral side of the inner member 100. The inner member 100 is made of a brazing material clad plate material, and specifically, an aluminum core material (A3003) and an aluminum brazing material (A434).
It is composed of a plate material obtained by cladding the skin material of 3) on both sides. FIG. 3A shows the shape of the brazing clad plate 101 constituting the inner member 100 before bending, and the plate 101 is rectangular.

At the ends of both long sides of the plate member 101, a slot-shaped groove 1 for forming an insertion hole for the flat tube 14 is formed.
02 and 103 are punched in parallel. Further, an insertion hole 104 of the separator 18 is punched in the center of the plate material 101. However, this insertion hole 10
4 is only provided on the plate material 101 for the second header tank 12, and need not be provided on the plate material 101 for the first header tank 11.

On the other hand, the outer member 110 is also made of a brazing clad plate material, and specifically, is made of an iron-based material (S35C) having a sufficiently high tensile strength and a small linear expansion coefficient than aluminum. It is used as a core material, and is made of a plate material in which a skin material made of aluminum brazing material (A4343) is clad on both surfaces on the surface of the iron-based material.
The plate constituting the outer member 110 may be a simple rectangular flat plate having no punched portion. FIG. 4 shows a comparison of various characteristics of the iron core material (S35C) of the outer member 110 and the aluminum core material (A3003) of the inner member 100.

Next, a method of assembling the first and second header tanks 11 and 12 in the first embodiment will be described. The plate member 101 of the inner member 100 is formed by a groove 10 shown in FIG.
After pressing into a rectangular flat plate shape having two and 103, as shown in FIG. 3 (b) (FIG. 2 (b) is also in the same state), both ends of the long sides are overlapped ( Bending (rolling) into a cylindrical shape (so that the elongated holes 102 and 103 overlap).

On the other hand, after the plate material of the outer member 110 is pressed into a simple rectangular flat plate shape without a punched portion,
The cylinder is bent (rolled) into a circular cross-sectional shape with a part of the circumferential surface cut away. FIG. 3C shows the outer member 110 after the bending. Here, the outer member 1
When bending the plate material of No. 10, even if springback occurs after the bending process, a predetermined shape (predetermined dimension) for holding the tank shape of the inner member 100 is obtained.
Set the bending of the plate.

A cylindrical inner member 100 is provided inside the outer member 110 bent into an arc-shaped cross section.
Are fitted by sliding in the axial direction. FIG. 3D shows a state after the two members 100 and 110 have been fitted. As described above, once the inner member 100 is fitted inside the outer member 110, the outer member 110 can reliably prevent the inner member 100 from trying to expand.

For this reason, the overlapping state of the elongated groove portions 102 and 103 can be reliably maintained at the proper position. Therefore, FIG.
As shown in (e), when the flat tube 14 is inserted into the tube insertion hole formed by the elongated groove portions 102 and 103, the tube insertion operation can be easily performed. By the way, as a whole, the condenser is assembled in a state shown in FIG. 1, and the assembled body is held by an appropriate jig, carried into a brazing heating furnace, and subjected to a brazing temperature (in the case of aluminum brazing, Heat the assembly to about 600 ° C)
The entire assembly is brazed together to form a condenser 1 shown in FIG.
Complete 0.

In this integral brazing step, 600
Although the assembled body is heated to a high temperature of about ° C, the iron-based core material (S35C) of the outer member 110 has an aluminum core material (A3
003), the amount of thermal deformation is small even at the time of heating to the brazing temperature. Therefore, even in the brazing process, the inner member 1 by the outer member 110 is used.
00 can be reliably maintained.

Therefore, it is possible to reliably prevent the tube from falling off during the brazing process or a defect such as a joint failure (seal defect) between the inner member 100 and the tube 14 due to the expansion of the inner member 100. Further, according to the first embodiment, the first and second header tanks 11 and 12 are as follows.
The effect of making the unit compact can also be achieved. That is, since the tensile strength of the iron-based core material (S35C) of the outer member 110 is much higher than the aluminum core material (A3003) of the inner member 100 as shown in FIG. At the time of design, the total thickness of the header tank required to obtain the same pressure resistance performance can be made significantly thinner than the conventional structure shown in FIG.

This will be described with reference to a specific design example. In the conventional structure shown in FIG. 5, the first and second header tanks 11 and 12 are made of only an aluminum clad plate material corresponding to the inner member 100 of the first embodiment. It is composed of In the case where the total thickness of the header tanks 11 and 12 having the conventional structure is, for example, 3 mm, in the first embodiment,
In order to obtain equivalent or higher pressure resistance performance, the thickness of the iron-based core material (S35C) of the outer member 110 is set to 0.35 mm, and the sum of the thickness of the skin material of the outer member 110 and the total thickness of the inner member 100 is set. May be set to 1.5 mm.

According to this, the total thickness of the header tanks 11 and 12 is 0.35 mm + 1.5 mm = 1.85 mm, which can be made 1 mm or more thinner than the total thickness (3 mm) of the conventional structure. The ratio of the thickness reduction is extremely large, and the header tanks 11 and 12 can be made compact. At the same time, the iron-based core material of the outer member 110 (S35C)
Tensile strength per density (tensile strength / density)
Is the aluminum core (A) of the inner member 100 as shown in FIG.
Since it is much larger than that of 3003), weight reduction of the header tanks 11 and 12 can also be achieved.

(Second Embodiment) FIG. 6 shows a second embodiment in which the bent ends of the inner members 100 are merely abutted but not overlapped. Even in this case, the same effect as in the first embodiment can be exerted by fitting the outer member 110 on the outer peripheral side of the inner member 100.

(Third Embodiment) FIG. 7 shows a third embodiment in which two substantially cylindrical inner members 100 are joined in a spectacle-like shape in cross section, and the inside of the header tanks 11 and 12 is divided into two passages. It is intended to be partitioned. Accordingly, the shape of the outer member 110 is processed into a shape having two arc-shaped portions along the outer peripheral surfaces of the two inner members 100. Even in this case, the same effects as in the first and second embodiments can be exerted.

(Other Embodiments) In the first embodiment, the brazing clad plate material 10
Slotted grooves 102 and 103 for forming the insertion hole of the flat tube 14 are punched at the end of one long side, but instead of the slotted grooves 102 and 103, A long hole (having a hole shape that does not open at the end) is punched out so as to be adjacent to the end of the long side of the plate material 101, and the long hole is overlapped to form a tube insertion hole. Is also good.

In the above embodiment, the case where the present invention is applied to the condenser in the vehicle air conditioner has been described. However, the present invention is not limited to the condenser and is widely applied to heat exchangers for various applications. It is possible.

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing a condenser according to a first embodiment of the present invention.

2A is a cross-sectional view of a header tank portion in the condenser of FIG. 1, and FIG. 2B is a perspective view of an inner member shown in FIG.

FIGS. 3A to 3E are explanatory views showing a method of assembling a header tank in the first embodiment.

FIG. 4 is a table showing characteristics of materials of an inner member and an outer member in the first embodiment.

FIG. 5 is a cross-sectional view of a header tank portion having a conventional structure.

FIG. 6 is a cross-sectional view of a header tank section showing a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of a header tank section showing a third embodiment of the present invention.

[Explanation of symbols]

10: condenser, 11, 12: first and second header tanks,
13 core part, 14 flat tube, 100 inner member, 101 plate, 110 outer member, 102, 103
… Elongated groove that forms the tube insertion hole.

Claims (5)

[Claims] 1. A plurality of flat tubes (1) arranged in parallel.
4) and a header tank (11, 12) in which both ends of the flat tube (14) are joined and communicate with each other, wherein the header tank (11, 12) has a brazing surface on a core material. Member (100) formed by bending a plate material (101) provided with a skin material made of a material into a substantially cylindrical shape.
The inner member (100) includes the flat tube (1).
The tube insertion hole (1) where the end of 4) is inserted and joined
02, 103) are provided. Further, an outer member (110) for maintaining the substantially cylindrical tank shape of the inner member (100) is integrally joined to the outer peripheral side of the inner member (100). A heat exchanger. 2. The heat exchanger according to claim 1, wherein the outer member (110) is made of a material having a lower coefficient of thermal expansion than the inner member (100). 3. The heat exchanger according to claim 1, wherein the outer member (110) is made of a material having higher tensile strength than the inner member (100). 4. The heat exchanger according to claim 3, wherein the outer member (110) is made of a material having a higher tensile strength per density than the inner member (100). 5. The outer member (110) is made of an iron-based material, and the plate (101) constituting the inner member (100) is
The heat exchanger according to any one of claims 1 to 4, wherein the heat exchanger is made of a plate material in which a skin material made of an aluminum brazing material is provided on a core material made of an aluminum-based material.