JPH08145591A - Heat exchanger - Google Patents

Abstract

PURPOSE: To permit sure brazing of the inserting part of a flat tube into a header tank by a method wherein the end of the flat tube is divided and formed so that a plurality of ends, having individual passages, are provided while the side end rims of respective ends are brazed. CONSTITUTION: A flat tube 2 is formed of two sheets of superposed plates 13A, 13B, formed so as to have a configuration having a predetermined size. The end of the flat tube 2 is divided into a plurality of parts or two divisions, for example, so as to have two ends 17, 18 while respective ends 17, 18 are provided with individual passages 17a, 18a and the end rims 17b, 18b are brazed. The inserting hole 7 of the header tank 4 is formed so as to have a configuration suitable for the divided configuration of the flat tube 2. According to this method, production of a gap at the ends 17, 18 of the flat tube 2 can be prevented when the flat tube 2 is incorporated into the inserting hole 7 of the header tank 4 whereby the brazing of the flat tube 2 to the header tank 4 can be effected surely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger of the type in which a tube insertion hole is formed in a header pipe, and a flat tube coated with a brazing material is inserted into the tube insertion hole to be brazed. .

[0002]

2. Description of the Related Art Conventionally, a plurality of flat tubes are laminated, and both ends of each flat tube are connected to a header tank, and a heat exchange medium meanders a plurality of times between inlet and outlet joints provided in the header tank. Stacked heat exchangers are known that flow through.

As a flat tube of this type of laminated heat exchanger, for example, as shown in FIG. 11, two plates 21, 21 made of a brazing sheet of a predetermined size are used.
A number of beads (protrusions) whose tip surfaces abut on each other
2, 22 are formed, and the joint portions 23, 23 of both side edges are formed.
It is known that the flat tube 20 is formed by joining the flat tubes 20 by brazing. Also known is one formed by bending a single plate.

When brazing a laminated heat exchanger using such flat tubes, fins are interposed between the flat tubes so that both ends of the flat tubes are inserted into the tube insertion holes of the header tank. After being inserted and assembled in a furnace and assembled with a jig, integrated brazing is performed in the furnace, and the tube insertion hole of the flat tube and the flat tube or the bead ends of the flat tube are joined to each other to be manufactured. .

[0005]

However, in the conventional flat tube for the heat exchanger, the insertion width of the insertion hole of the header tank is formed substantially parallel to the tube insertion direction, and the insertion hole is brazed. Deformation due to heating during brazing, thinning of the brazing sheet brazing material, thinning of gas generated inside the tube during brazing to the outside, and pressure applied by jigs during brazing In particular, in the header tank insertion portion of the flat tube, a gap is generated in the contact portion to be brazed, and, for example, as shown in FIG. 12, a fin is provided between the header tank 24 and the fin 25. There is an inconvenience that the brazing property at the insertion portion S of the flat tube 20 where 25 is not provided deteriorates.

To solve this problem, if the pressure applied to the jig during assembly is increased, problems such as buckling of the fins during heating during brazing will occur anew, and the flat tube header will be more difficult than in the past. There has been a demand for improved brazability near the tank insertion part.

With respect to this point, conventionally, as shown in FIG. 13, a hole portion 26 is formed in one of the front end surfaces of the pair of beads 22, 22, which are in contact with each other, and a hole is formed during brazing. A brazing material is introduced to the periphery of the portion 26 to improve the brazing property (first in JP-A-4-20794).
Example), as shown in FIG. 14, of the pair of beads 22, 22 that abut against each other, a hole portion 26 is formed on one of the tip surfaces, and the hole portion 26 is formed on the other tip surface.
Provided with a protrusion 27 that fits in the
No. 94 second embodiment), as shown in FIG. 15, of the pair of bead 22, 22 abutting against each other, one tip surface has a conical small projection 28, and the other tip surface has the above-mentioned The one provided with a conical small recess 29 that fits into the small projection 28 (Actual No. 5-71676) is proposed.

However, the structure disclosed in Japanese Patent Laid-Open No. 20794/1992, the structure in which a protrusion is fitted in the hole, and the actual flat structure 5-716.
No. 76, which has a structure of a conical small projection and a small recess that fits into this small projection, has a bead with a small area and further has a hole or a projection, a conical small projection or a small projection. Since the recesses are formed, these holes, protrusions, etc. have a smaller area than a small area bead, and therefore extremely precise processing technology is required, and it is difficult to actually manufacture them. However, the dimensional accuracy became non-uniform, and it was impossible to ensure good engagement of the front end faces of the beads. Particularly in the latter two cases, when the beads are not sufficiently engaged with each other, the insufficient position is maintained, so that good engagement of the front end surfaces of the beads cannot be ensured. It was

Therefore, the present invention provides a heat exchanger in which the ends of the flat tubes are improved so that the plates can be brought into a positively engaged state and brazing can be efficiently performed in that state. Is intended.

The present invention is a heat exchanger of the type in which the end portion of the flat tube is inserted into the tube insertion hole of the header tank and brazed, and as described above, fins are provided between the header tank and the fins. Analysis of the cause of deterioration of the brazing property in the flat tube insertion portion S (see FIG. 12) revealed that brazing was almost certain for the joints on both side edges of the flat tube. It was made based on. That is, it is proposed that a structure similar to the joint portion of the flat tube-side edge with reliable brazability be extended to and formed at a portion other than the joint portion.

[0011]

SUMMARY OF THE INVENTION According to the present invention, a heat exchange is of a type in which a tube insertion hole is formed in a header pipe, and an end portion of a flat tube coated with a brazing material is inserted into the tube insertion hole to be brazed. In the container, the end of the flat tube is divided into a plurality of ends to form a plurality of ends, and each of the divided ends has a separate passage and a side edge is brazed. It is an exchange.

In the heat exchanger, the end portion and an end portion adjacent to the end portion are separated from each other, and the end portion and an end portion adjacent to the end portion are partially connected. Aspects, and further, an aspect in which the end portion and an end portion adjacent thereto are connected to each other are suitable as embodiments.

In this case, it is preferable that the tube insertion hole has a shape adapted to the divided shape of the end portion.

[0014]

In this structure, each end of the flat tube which is formed by dividing the end of the flat tube has an individual passage and the side edges are brazed. Each side edge of the end portion is similar to the original side edge joint portion of the flat tube, and as a result, a portion where brazability is improved, that is, each side edge portion of each end portion is Since it is formed on the side edge other than the original side edge, it is possible to reliably braze the flat tube insertion portion S in which the fins are not provided.

[0015]

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

In FIG. 1, the flat tube 2 of this embodiment is shown.
In the laminated heat exchanger 1 using, a plurality of flat tubes 2 are laminated with corrugated fins 3 interposed therebetween.

As shown in FIG. 2, each end portion of the plurality of flat tubes 2 is inserted into an insertion hole 7 provided in the header tank 4 with a bead fitted in a hole of a flat surface portion described later. The wavy fins 3 are provided in the range of symbol S in FIG.
Is not provided.

The upper and lower openings of each header tank 4 are closed by a blind cap 8, and a partition plate 9 is provided at a predetermined position of each header tank 4.

Further, the header tank 4 is provided with an inlet joint 10 and an outlet joint 11, and these inlet and outlet joints 1
The heat exchange medium meanders a plurality of times between 0 and 11 and flows.

In FIG. 1, reference numeral 12 denotes side plates arranged above and below the laminated flat tubes 2.

As shown in FIG. 3, each of the flat tubes 2 has two plates 13A and 13B formed into a predetermined size by, for example, roll forming or press forming.
Are formed by overlapping. These plates 13
A and 13B have joint portions 14 and 14 on their peripheral edges, and are formed so that the respective flat surfaces 15 and 15 bulge outward, and the front surfaces of the flat surfaces 15 are in contact with each other. A large number of beads (protrusions) 16 are provided.

The beads 16 are provided in a plurality of rows in the width direction of the flat tube 2, and the beads 16 cause a turbulent flow in the heat exchange medium flowing inside the tube 2 to enhance the heat exchange capacity. The structure is such that the strength of the tube flat surface 15 is increased and the pressure resistance is improved.

Further, in the case of the embodiment, the end portion of the flat tube is divided into two portions to provide two end portions 17 and 18, and each end portion 17 and 18 has an individual passage 17a and 18a. And the side edges 17b, 18b are brazed. In this example, the two ends 17 and 18 are provided separately.

As described above, in the present invention for securely brazing the insertion portion S of the flat tube without fins, the two end portions 17 and 18 thus formed are basically Specifically, it is provided in a portion where the fin is not provided. However, the formation length is appropriately selected according to the size of the heat exchanger in which the present invention is implemented.

Further, since the end portion of the flat tube is divided and provided with the two end portions 17 and 18, the header tank 4
The insertion hole 7 is formed in a shape that fits the divided shape, as shown in FIGS. In the embodiment, the insertion hole 7 is
Two large holes 7a, 7 corresponding to the two ends 17, 18
a, and a small hole portion 7b corresponding to the side edges 17b, 18b.
have. It should be noted that, as shown in FIG. 6, the insertion hole 7 is formed into two large hole portions 7a corresponding to the two end portions 17 and 18,
It is also possible to form only 7a.

Next, the point of forming a heat exchanger using the flat tube having the above structure will be described.

In order to form the flat tube 2, a plate made of a brazing sheet having a predetermined width wound on a roll is sequentially fed out from the roll, and upper and lower dies (rollers or the like) are used to join the flat surface 15 and both side portions. The portion 14 and the bead 16 are formed. In the flat tube 2 according to the present embodiment, the two end portions 17 and 18 are formed by pressing when the joint portion 14 and the bead 16 are formed or after that. Then, by cutting the two end portions 17 and 18 with a cutter, the respective plate 13
A and 13B are formed.

Next, the flat plates 2 are assembled by superposing the two plates 13A and 13B formed as described above and bringing the beads 16 into contact with each other.

After that, the fins 3 are interposed between the plurality of flat tubes 2 and both ends of the flat tubes 2 are inserted into the tube insertion holes 7 of the header tank 4 (FIG. 7) and assembled by a jig. , Brazing is performed integrally in the furnace, the tube insertion hole 7 and the flat tube 2, and the bead 1 of the flat tube 2
6 are joined together. At this time, the molten brazing material is 2
Between the two ends 17, 18 and the tube insertion hole 7
And the flat tube 2, and the ends 17 and 1 of the flat tube 2.
The side edges 17b and 18b of No. 8 are securely brazed and joined.

Therefore, in a flat tube constructed by superposing two plates, two end portions 1 formed in two parts are provided on the plates 13A and 13B which are in contact with each other.
7 and 18 are provided, the insertion hole 7 of the header tank 4
Even when the flat tube 2 is assembled with the flat tube 2, it is possible to prevent a gap from being generated at the end portion of the flat tube, and it is possible to reliably braze these.

As a result, there is no influence of the shape of the insertion hole of the header tank, the deformation of the insertion hole due to heating, the absence of the pressing force of the jig, and the pressing force of the jig during assembly. There is no need to strengthen it, and problems such as fin buckling do not occur.

The plates 13A and 13B are advantageous in terms of mold economy when the same plates are used symmetrically. However, the present embodiment is not limited to this, and another shape may be used.

Next, another embodiment of the present invention will be described.

In the embodiment shown in FIG. 8, as in the previous example, the flat tube 2 has two plates 13A, 1 formed into a predetermined size by, for example, roll forming or press forming.
3B are overlapped with each other, and these plates 13A and 13B have joint portions 14 and 14 at their peripheral portions, and the respective flat surfaces 15 and 15 are formed so as to bulge outward. A large number of circular beads 16 and 16 projecting inward are provided on the flat surface 15.

In the present embodiment, the end of the flat tube is further divided into two parts as in the previous example, and the two end parts 17 and 1 are formed.
8 and each end 17, 18 has a separate passage 17
a, 18a and side edges 17b, 18b are brazed. The two end portions 17 and 18 are not long enough to be located in the header tank 4, so that the flat tube 2 of this embodiment inserted into the header tank 4 is
The flat surface 15 is joined to the insertion hole 7 having a conventional shape.
In addition, an elliptical bead 160 is provided at a portion located outside the flat surface 15 that is joined to the insertion hole 7 to improve the brazability of the plates 13A and 13B.

In the embodiment shown in FIG. 9, similarly to the previous example, the flat tube 2 is composed of two plates 13A, 1 which are formed into a predetermined size by, for example, roll forming or press forming.
3B are overlapped with each other, and these plates 13A and 13B have joint portions 14 and 14 at their peripheral portions, and the respective flat surfaces 15 and 15 are formed so as to bulge outward. A large number of circular beads 16 and 16 projecting inward are provided on the flat surface 15.

In the present embodiment, the end of the flat tube is further divided into two parts as in the previous example, and the two end parts 17 and 1 are formed.
8 and each end 17, 18 has a separate passage 17
a, 18a and side edges 17b, 18b are brazed. The side edges 17b and 18b of the two end portions 17 and 18 are partially connected by a connecting portion 19. When the connecting portion 19 is provided and partially connected as described above, it is possible to avoid twist deformation due to residual stress that is likely to occur particularly during brazing.

Further, in the case of the embodiment shown in FIG. 9, by using the insertion hole 7 of the header tank 4 shown in FIG. 6, the portion of the connecting portion 19 also functions as a stopper when the tube is inserted.

Further, another embodiment of the present invention will be described.

In the embodiment shown in FIG. 10, as in the previous example, the flat tube 2 has two plates 13A, which are formed into a predetermined size by, for example, roll forming or press forming.
These plates 13A and 13B have joint portions 14 and 14 at their peripheral portions, and the respective flat surfaces 15 and 15 are formed so as to bulge outward. A large number of circular beads 16 and 16 projecting inward are provided on the flat surface 15.

In the present embodiment, the end of the flat tube is further divided into two parts as in the previous example, and the two end parts 17 and 1 are formed.
8 and each end 17, 18 has a separate passage 17
a, 18a, the side edges 17b, 18b of the above embodiment
The portion corresponding to (1) is not a unitary joint portion 140, 140, that is, the end portions 17, 18 are connected to each other, and these joint portions 140, 140 are brazed. Also in this case, it is possible to avoid twist deformation of the tube end portion due to residual stress that tends to occur during brazing as much as possible.

Further, as shown in FIG. 10, the end portions 17, 1
A pin 30 made of the same material as the tube may be mounted between the pins 8. The pin 30 is a U-shaped member having pieces 31 and 32, and the interval between the pieces 31 and 32 is the above-mentioned joining portions 140 and 14.
The thickness is 0 or the thickness of the side edges 17b and 18b when the flat tube 2 shown in FIGS. 3, 8 and 9 is used. When the pin 30 is used, the joint at the end of the flat tube 2 is reinforced and the gap is filled / complemented, and the pin 30 is also brazed at the same time. Therefore, the joint is reinforced and the gap is filled / complemented. Combined with this, it is possible to bring about an improvement in brazability.

In the above embodiment, the flat tube 2 is formed by superposing two plates, but the flat tube 2 is not limited to this, and one plate which has been conventionally used is bent. The same can be applied to those formed by overlapping with each other. In this case, due to the springback caused by bending,
There is an advantage that it is possible to surely prevent the generation of the gap between the plates, especially the gap at the end of the tube.

Further, in the embodiment, the end of the flat tube is divided into two and has two ends, but in the case of a comparatively large tube, the end is formed more than that. Needless to say, the present invention is not limited to the number of divided ends in the embodiments.

[0045]

As described above, according to the present invention, each of the end portions of the flat tube, which are formed by dividing the end portion, is provided.
Having separate passages and brazed side edges, each side edge of each end is similar to the original side edge joint of the flat tube, resulting in a braze. Since the part where the attaching property is improved, that is, each side edge of each end is formed in addition to the original side edge, the insertion portion S of the flat tube where the fin is not provided will be surely secured. Can be attached.

As described above, according to the present invention, since the brazing property of the tube end portion without the fin can be improved, it is possible to obtain the heat exchanger having the improved pressure resistance.

[Brief description of drawings]

FIG. 1 is a front view of a laminated heat exchanger according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing an end portion of a flat tube inserted into an insertion hole of a header tank.

FIG. 3 is a perspective view showing a flat tube.

FIG. 4 is a perspective view showing an end portion of a header tank and a flat tube.

FIG. 5 is a view showing an insertion hole of a header tank.

FIG. 6 is a view showing an insertion hole of a header tank.

FIG. 7 is a cross-sectional view showing a state in which the end portion of the flat tube is inserted into the insertion hole of the header tank.

FIG. 8 is a vertical cross-sectional view of a flat tube according to another embodiment of the present invention.

FIG. 9 is a vertical cross-sectional view of a flat tube according to another embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view of a flat tube according to another embodiment of the present invention.

FIG. 11 is a vertical cross-sectional view of a flat tube according to a conventional example.

FIG. 12 is a vertical cross-sectional view showing an end portion of a flat tube inserted into an insertion hole of a header tank according to a conventional example.

FIG. 13 is a longitudinal sectional view showing a main part of a flat tube according to a conventional example.

FIG. 14 is a longitudinal sectional view showing a main part of a flat tube according to a conventional example.

FIG. 15 is a vertical cross-sectional view showing a main part of a flat tube according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated heat exchanger 2 Flat tube 4 Header tank 7 Insertion hole 13A plate 13B plate 14 Joining part 15 Eccentric plane 16 Bead 17 End part 17a Passage 17b Side end edge 18 End part 18a Passage 18b Side end edge 19 Joining part 140 Joining Department

Claims (5)

[Claims] 1. A heat exchanger of the type in which a tube insertion hole is formed in a header pipe, and the end portion of a flat tube coated with a brazing material is inserted into the tube insertion hole to be brazed. A heat exchanger characterized in that the end portion is divided and formed to provide a plurality of end portions, and each of the divided and formed end portions has an individual passage and a side end edge is brazed. 2. The heat exchanger according to claim 1, wherein the end portion and an end portion adjacent to the end portion are separated from each other. 3. The heat exchanger according to claim 1, wherein the end portion and an end portion adjacent to the end portion are partially connected to each other. 4. The heat exchanger according to claim 1, wherein the end portion and an end portion adjacent to the end portion are connected to each other. 5. The heat exchanger according to claim 1, wherein the tube insertion hole has a shape that matches the divided shape of the end portion.