JPH08145586A - Flat tube for heat exchanger - Google Patents

Abstract

PURPOSE: To engage plates mutually across the whole surfaces surely and permit brazing efficiently under the engaged condition by a method wherein a plurality of beads are formed on a plate and the opposing site of the beads to the plate is formed so as to be a flat surface, further, the opposing site of the plate is provided with a bead engaging hole. CONSTITUTION: Plates 13A, 13B are provided with flat surfaces inflated outwardly while respective flat surfaces 15 are provided with a multitude of circular beads 16 projected inwardly. Further, holes 17, into which the beads 16 are fit, are formed on the plates 13A, 13B at the parts opposed to respective beads 16. The holes 17 and the beads 16, fit into the holes 17, are formed in such a manner whereby both of the plates 13A, 13B are connected surely upon brazing. According to this method, the plates 13A, 13B are engaged surely across the whole surfaces thereof mutually while brazing can be effected efficiently under such a condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat tube for a heat exchanger, which is formed by bending one plate or stacking two plates.

[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 is meandered a plurality of times between inlet and outlet joints provided in the header tank. Flowing laminated heat exchangers are known.

As a flat tube of this type of laminated heat exchanger, for example, as shown in FIG. 8, a large number of plates whose tip surfaces are in contact with each other are two plates 21 and 21 made of a brazing sheet of a predetermined size. Bead 22,
It is known that the flat tube 20 is formed by joining the joint portions 23, 23 on both edges 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. Since it is easily deformed by heating at the time, and further, there is no pressing force by the jig during brazing, a gap is created at the contact portion to be brazed, especially in the header tank insertion part of the flat tube, For example, as shown in FIG. 9, it has been pointed out that the brazing property at the insertion portion S of the flat tube 20 where the fin 25 is not provided between the header tank 24 and the fin 25 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. There has been a demand for improved brazability near the header tank insertion part.

Regarding this point, conventionally, as shown in FIG. 10, 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. 11, 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. 12, 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

Incidentally, in the case of a normal type flat tube in which four rows of beads are formed at a pitch of 3 mm in a tube length of 600 mm, the number of beads is 800 pieces / 1 piece.
There are 24,000 beads in total in a heat exchanger having 0 tubes. Of these 24,000 beads, two plates are joined together to form a set, so if you focus on the beads themselves, there are 48,000 beads for each. There is. Since pressure resistance is not satisfied unless all these beads are brazed, it is necessary to control the height of the beads, but it is necessary to control the height of 48,000 beads with one heat exchanger. Considering mass productivity, it is extremely difficult. From this point of view, it is actually not preferable to further process something on the bead.

Therefore, the present invention can improve the flat tube to bring the plates in the vicinity of the header tank insertion portion of the flat tube, as well as the plates, into a state in which they are securely engaged over the entire surface thereof. It is an object of the present invention to provide a flat tube for a heat exchanger that enables efficient brazing in a state.

[0011]

According to a first aspect of the present invention, in a flat tube for a heat exchanger, which is formed by bending one plate or stacking two plates, a plurality of beads are formed on the plate. In addition, a flat tube for a heat exchanger, in which all or part of the bead is formed to have a flat facing portion of the plate, and the facing portion of the plate has a hole into which the bead is fitted. .

According to a second aspect of the present invention, in a flat tube for a heat exchanger, which is formed by bending one plate or stacking two plates, a plurality of beads of high and low stages are formed on the plate. , Forming the facing portion of the plate where the high and low two-stage beads face each other on a plane, and further forming a hole into which the higher bead fits in the portion of the plate where the higher bead of the plate faces. And the lower bead is a flat tube for a heat exchanger that abuts the flat surface of the plate.

[0013]

The flat tube of this kind is formed by bending one plate or by superposing two plates and brazing them together. In this case, the beads can be bent before the plates are folded or overlaid, or at the same time.
It is formed by roll processing, press processing, die processing, or the like.

Further, in the case of the first invention of the present application, since the facing portion of the plate where all or a part of the bead faces is formed in a flat surface, at least a part of the bead is a flat portion of the plate. opposite. Then, since the hole into which the bead is fitted is formed in the flat portion of the plate, the bead engages with the hole.

Further, in the case of the second invention of the present application, among the plurality of high-low two-stage beads formed on the plate, the higher bead is the same as the first invention, and the bead is on the plate flat portion. It engages the formed hole and the lower bead abuts the flat portion of the plate.

Thereafter, fins are interposed between the plurality of flat tubes, and both ends of the flat tubes are inserted into the tube insertion holes of the header tank, assembled by a jig, and then integrally brazed in the furnace. The tube insertion hole of the flat tube and the flat tube and the bead circumference of the flat tube are joined together.

Therefore, even if the flat tube is formed by bending one plate or by stacking two plates, at least some of the beads are formed on the plane of the other plate. Since the engaging structure that fits into the formed hole is formed, when the flat tube is assembled in the insertion hole of the header tank, the positioning thereof can be extremely easily performed. That is, in the past, precise dimension control was performed, and there were locations where brazing could not be performed unless the height dimensions were particularly uniform, but according to the present invention, the bead fits into the hole Even if the management is relatively rough, the bead fits into the hole and the engaging structure can be easily obtained.

Further, since the hole into which the bead is fitted communicates with the inside and outside of the plate, the molten brazing material flows into the hole from inside and outside of the plate, and the bead and the engaging portion of the hole are securely brazed and joined. The plate can be brazed reliably, and the brazability of the flat tube at the header tank insertion portion can be improved.

If a problem occurs in brazing,
Since the brazing point is visible from the outside, the brazing can be easily confirmed by the airtight test.

As described above, according to the present invention, 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 like.
Also, there is no need to increase the pressure of the jig during assembly,
There is no problem such as buckling of the fins.

[0021]

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
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 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, for example, each flat tube 2 is formed into a predetermined size and shape by roll-forming, press-forming or the like while continuously supplying an aluminum brazing sheet coated with a brazing material. The two plates 13A and 13B are overlapped with each other.

These plates 13A and 13B have joints 14 and 14 at their peripheral portions, and their respective flat surfaces 15 and
15 is formed so as to bulge outward. Each flat surface 15
Is a circular bead that protrudes inward (projection) 1
A large number of 6 and 16 are provided. In addition, this plane 15
Using the flat surface of the material as it is, the joint portion 14 and the bead 16 are formed by roll, press, or the like.

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 of enhancing the strength of the tube flat surface 15 and improving the pressure resistance.

Further, the facing portion of the plate on which the beads 16, 16 provided on the flat surface 15 face each other uses the flat surface of the material on the flat surface 15 as described above. A hole 17 into which the bead 16 is fitted is formed in the facing portion. And these beads 16
Has a uniform projecting height, and the flat surface 15 of the other plate
The edge of the bead tip is joined to the inner edge of the hole 17. Thus, in this embodiment, these holes 1
7 and the bead 16 to be fitted to this are formed,
At the time of brazing described later, both plates 13A, 13B
Will be reliably joined.

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 the upper and lower molds are used to form the flat surface 15, the joint portions 14 on both sides, and the bead. The plates 13A and 13B are formed by forming 16 and holes 17 and cutting them to a predetermined length with a cutter.

Next, the two plates 13A and 13B formed as described above are overlapped with each other, and the tip end of the bead 16 is fitted into the hole 17 to assemble the flat tube 2.

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. In this example,
Since the tip end surface of the bead 16 is flush with the flat surface 15 or slightly buried, the bead 16 can be inserted without being caught in the insertion hole 7. After assembling with a jig, integral brazing is performed in the furnace to join the tube insertion hole 7 and the flat tube 2, and the bead 16 and the hole 17 of the flat tube 2. At this time, the melted brazing material flows into the hole 17 from inside and outside of the flat surface 15, and the bead 16 and the hole 17
The engaging portions of are securely brazed and joined.

Therefore, even if the flat tube is constructed by superposing two plates, the bead 16 and the hole 1 which are fitted to each other are fitted to the plates 13A and 13B which are in contact with each other.
7 is formed, the insertion hole 7 of the header tank 4 is formed.
Even when the flat tube 2 is assembled with the flat tube 2, it is possible to prevent a gap from being produced between the flat tube joints, and it is possible to reliably braze these.

As a result, the shape of the insertion hole of the header tank, the deformation due to heating of the insertion hole, the absence of the pressing force of the jig, and the like are not affected, and the pressing force of the jig during assembly is reduced. 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. 5, as in the previous example, the flat tube 2 has two plates 13A, which are formed into a predetermined size and shape 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. The beads 16 are provided in a plurality of rows in the width direction of the flat tube 2, and each of the beads 16 provided on the flat surface 15,
The facing portion of the plate facing 16 is a flat surface 15
It is formed in a plane with, further, in the bead facing portion,
A hole 17 into which the bead 16 fits is formed.

In the present embodiment, these beads 16 have a uniform projecting height and extend to the flat surface 15 of the other plate, and the peripheral edge of the bead tip is joined to the inner peripheral edge of the hole 17. Unlike the previous example, the bead tip surface projects from the hole 17. As described above, in this embodiment, the fitting is more reliable, which is advantageous for the brazability.

In the case of this example, considering that both ends of the flat tube 2 are inserted into the tube insertion holes 7 of the header tank 4, only the both ends of the flat tube 2 are, as in the previous example, the tip surface of the bead 16. It is also possible to consider that is equal to or less than the same plane position as the plane surface 15. However, when the projecting height of the bead tip surface projecting from the hole 17 is small, when the both ends of the flat tube 2 are inserted into the tube insertion holes 7 of the header tank 4, the projecting state does not hinder. , Rather,
Brazing property is secured.

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

In the embodiment shown in FIG. 6, similarly to the previous example, the flat tube 2 has two plates 13A, 1 formed in a predetermined size and shape by, for example, roll forming or press forming.
These plates 13A and 13B are formed by superimposing 3B on top of each other, and each of the plates 13A and 13B has a joint portion 14 and 14 at the peripheral edge thereof, and the respective flat surfaces 15 and 15 are formed to bulge outward.

In this embodiment, a plurality of high and low tiered beads 16 and 160 are formed on the plates 13A and 13B, and the facing portions of the plate on which the high and low tiered beads 16 and 160 face each other are formed on a flat surface. , That is, plane 15
Is used as it is, and a hole 17 into which the higher bead 16 fits is formed in a portion of the plate where the higher bead 16 of the plate faces, and the lower bead 160 is This structure is in contact with the flat surface (flat surface 15).

In the case of this embodiment, the number of holes 17 is smaller than that of the above-mentioned embodiments, so naturally it is possible to reduce the number of holes formed, which is suitable for labor saving of the work, and on the other hand, the bead is used. Since the 16 and the hole 17 have the engaging portions to be fitted to each other, it is possible to improve the reliability of the joining of the plates 13A and 13B. Further, from the viewpoint of the turbulent flow effect generated by the beads, it may be recently demanded to reduce the diameter of the beads. In this respect, in the present embodiment, the lower bead 160 can be made as small as possible, so that this requirement is met.

In the case of the embodiment shown in FIG. 6, the bead 160 is provided in the vicinity of the joint portions 14, 14 having a relatively high brazing property.
And the flat surface 15 are joined to each other, and the bead 1 is attached to the central portion where brazing is insufficient in comparison with the conventional one.
It is advisable to provide an engaging portion where 6 and hole 17 are fitted.

FIG. 7 shows an example in which a cylindrical curl portion 18 is formed inside the hole 17. That is, the curl portion 18 is burred when the hole 17 is formed, and in the embodiment, it is formed by a so-called eyelet forming punch. When the cylindrical curl portion 18 is formed inside the hole 17 as described above, it is convenient to avoid removing the scraps by pressing or the like, and in contacting the curl portion 18 with the bead 16, It is advantageous in terms of fitting and brazing of the hole 17 and the bead 16 such that the contact area can be increased.

In the above embodiment, the flat tube 2 has been described as being formed by stacking 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 superposing. In this case, there is an advantage that it is possible to surely prevent the generation of the gap between the plates due to the springback caused by the bending.

Further, in each of the above-mentioned embodiments, the case where each bead and the hole corresponding thereto has a circular shape has been described as an example, but the present invention is not limited to this, and each combination has an oval shape,
Other combinations such as circular shapes and oval shapes may be used.

[0050]

As described above, the present invention is a flat tube which is formed by bending one plate or is formed by stacking two plates.
Since at least a part of the beads has an engaging structure that fits into a hole formed in the flat surface of the other plate, when the flat tube is assembled in the insertion hole of the header tank, its positioning is extremely easy. obtain. That is, since the bead fits into the hole, the bead fits into the hole and the engaging structure can be easily obtained even if the dimensional control is relatively rough.

Further, since the hole into which the bead fits communicates with the inside and outside of the plate, the molten brazing material flows into the hole from inside and outside of the plate, and the bead and the engaging portion of the hole are securely brazed and joined. The plate can be brazed reliably, and the brazability of the flat tube at the header tank insertion portion can be improved.

In addition, even if a problem occurs in brazing,
Since the brazing point is visible from the outside, the brazing can be easily confirmed by the airtight test. Therefore, a highly reliable heat exchanger can be obtained.

Furthermore, in the case of a flat tube formed by bending one plate, there is an advantage that a springback caused by the bending can surely prevent the generation of a gap between the plates.

As described above, according to the present invention, the bead is fitted in the hole, and the hole is formed as a flat plane and is not separately processed into the bead. Unlike the requirement that precise dimensional accuracy is required when the hole is easily machined and the bead abuts against the other, the bead and hole fitting structure makes it possible to perform dimensional control very easily. Therefore, its manufacture is facilitated. Furthermore, the flat tube obtained by joining such plates has improved brazing property and hence pressure resistance,
When this flat tube is used, it is not affected by the shape of the insertion hole of the header tank, the deformation of the insertion hole due to heating, the lack of pressing force of the jig, and the like. This has the advantage that there is no need to increase the pressure applied to the plate and problems such as fin buckling do not occur.

[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 sectional view taken along line AA of FIG. 3;

FIG. 5 is a vertical cross-sectional view of a flat tube according to another embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of a flat tube according to another embodiment of the present invention.

FIG. 7 is a vertical cross-sectional view showing a bead and a hole portion into which the bead fits according to another embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of a flat tube according to a conventional example.

FIG. 9 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. 10 is a vertical cross-sectional view showing a main part of a flat tube according to a conventional example.

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

FIG. 12 is a longitudinal sectional view showing a main part of a flat tube according to a conventional example.

[Explanation of symbols]

 1 Laminated Heat Exchanger 2 Flat Tube 4 Header Tank 7 Insertion Hole 13A Plate 13B Plate 15 Flat Surface 16 Beads 17 Holes 18 Curl Section 160 Beads

Claims (4)

[Claims] 1. Bending one plate, or
In a flat tube for a heat exchanger formed by stacking two plates, a plurality of beads are formed on the plate, and the facing portion of the plate where all or part of the beads face each other is formed into a flat surface, and further. At the facing part of the plate,
A flat tube for a heat exchanger, wherein a hole into which the bead is fitted is formed. 2. The flat tube for a heat exchanger according to claim 1, wherein the bead fitted in the hole has a tip end surface protruding from the hole. 3. The flat tube for a heat exchanger according to claim 1, wherein a cylindrical curl portion is formed inside the hole. 4. Bending one plate, or
In a flat tube for a heat exchanger formed by stacking two plates, a plurality of high and low stages of beads are formed on the plate, and the facing portion of the plate where the high and low stages of beads are opposed to each other is formed on a flat surface. A hole into which the higher bead fits is formed in a portion of the plate where the higher bead of the plate faces, and the lower bead abuts the flat surface of the plate. A flat tube for heat exchangers.