JPH0218948B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method of manufacturing a heat exchanger used in evaporators for car air conditioners and the like.

Conventional technology and its problems Conventionally, this type of heat exchanger has a meandering flat tube that has a plurality of internal flow paths and straight tube sections that are parallel to each other, and a serpentine flat tube that has straight tube sections that are parallel to each other. A type with a corrugated fin interposed between the tubes and two headers attached to both ends of a flat tube is widely used.

Such a heat exchanger has been manufactured, for example, by the following method. That is, in Figure 4,
First, a meandering flat tube 11 made of an extruded aluminum tube is prepared, and a large corrugated fin 12 made of an aluminum brazing sheet is placed between adjacent straight tube portions 11a of the flat tube 11.
A side plate 14 is arranged on the outer surface of the straight pipe part 11a on one end side of the pipe through a small corrugated fin 15 made of the same sheet, and then a cylindrical header made of an aluminum brazing sheet is placed at both ends of the flat pipe 11. 13 is temporarily attached to the mounting hole 13a drilled in the cylindrical surface of the unjoined assembly 1 to form a heat exchanger.
Set it to 6. A pair of metal jig plates 17 for clamping, which were separately prepared, are used to connect two flat surfaces 11b and 14 parallel to the straight pipe portion 11a among the outer surfaces of the combination body 16 during vacuum brazing.
a, that is, a jig plate 17 provided with a large number of flat surface gas release holes 17a for releasing gas generated from the flat surface 11b of the upper outer surface of the flat tube 11 in FIG. 4 and the flat surface 14a that is the lower surface of the side plate 14. is applied to the two flat surfaces 11b and 14a. Next, the assembly 16 is temporarily fixed by tightening the metal tightening band 18 via both jig plates 17. Thereafter, by vacuum brazing, the straight pipe part 11a of the flat pipe 11, the large and small corrugated fins 12 and 15, and the small corrugated fin 1 are
A heat exchanger was manufactured by joining each end of the flat tube 11 and each header 13 to the side plate 14 and the header 13, respectively.

However, this method of manufacturing a heat exchanger by performing vacuum brazing using the jig plate 17 having only the flat surface gas escape holes 17a has the following problems. That is, the gas generated from the combination 16 during vacuum brazing is removed from the combination 16 as a pretreatment.
oil during the cleaning work applied to the structural members, oil during the caulking work before temporarily attaching the end of the flat tube 11 and the header 14, or volatile matter from the brazing sheet brazing material layer during vacuum brazing. It is derived from In addition, the jig plate 17 is provided with one
Generally, only different sizes are prepared and these are used for holding combinations 16 of various sizes.

Therefore, when the area of the flat surfaces 11b and 14a in the combination 16 is smaller than the area of one side of the jig plate 17, the jig plate 17 covers all or part of the header 13 together with the flat surfaces 11b and 14a. In some cases, the same flat surfaces 11b and 14a are applied. When vacuum brazing is performed under these conditions, some of the gas generated is
Attachment hole 13a in header 13, where the end of flat tube 11 and header 13 are joined
It accumulates between the jig plate 17 and a portion of the edge of the assembly 16 that is on the outer surface side. As a result, the surface of the part to be joined is covered with gas, and the brazing material is not completely fused to the same surface, resulting in poor joining and the failure of the heat exchanger as a product. Problems such as leakage occurred during use.

Such troubles occur particularly frequently when manufacturing a type of heat exchanger in which the header 13 is attached at a position where it contacts the jig plate 17, as shown in FIG.

Furthermore, as described above, the jig plate 17 is attached to the header 13.
The flat surface 11b of the combination body 16 covers the
If vacuum brazing was performed with the material 14a applied, the following problems also occurred.
That is, since there is no hole or the like in the position corresponding to the header 13 on the jig plate 17 as shown in FIG. 4, heat is taken away by the jig plate 17 during vacuum brazing, and the header 13 and flat tube 11
It takes a lot of time to heat the area to be bonded to the specified temperature, which results in a high rate of bond failure at the same area, and at the same time increases the consumption of thermal energy, resulting in higher product costs. .

This invention has been made in view of the above-mentioned circumstances, and is intended to connect the portion of the edge of the attachment hole in the header that is on the outer surface side of the combination body, which is the planned joint location between the end of the flat tube and the header. The gas generated during vacuum brazing does not remain between the fitting plate and the joint, which prevents joint defects at joints.Furthermore, by saving heat energy during vacuum brazing, product costs can be reduced. It is an object of the present invention to provide a method for manufacturing a heat exchanger that can also reduce the heat exchanger.

Means for Solving Problems The method for manufacturing a heat exchanger according to the present invention includes at least a serpentine flat tube having a plurality of internal flow paths and straight tube portions parallel to each other, and a method of manufacturing a heat exchanger by connecting adjacent straight tube portions. On the two flat surfaces parallel to the straight pipe part of the outer surface of the unjoined combination body formed by combining the corrugated fins interposed between them and the headers temporarily attached to both ends of the flat pipe with mounting holes, A pair of jig plates with a large number of flat surface gas escape holes are applied, and then a tightening band is used to tighten the assembly through both jig plates to temporarily fix the assembly, and then the predetermined parts of the assembly are joined by vacuum brazing. A method for manufacturing a heat exchanger, the method comprising: at least the one of a pair of jig plates that is in contact with a header or has a smaller distance from the header, in addition to a flat surface gas relief hole; Furthermore, a header joint gas release hole is provided at a position corresponding to the outer surface side of the assembly among the edges of the mounting hole in the header, and vacuum brazing is performed using these jig plates. .

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a meandering flat tube made of extruded aluminum tube having a plurality of channels inside and straight tube sections 1a parallel to each other, and 2 indicates a connection between adjacent straight tube sections 1a of the flat tube 1. A large corrugated fin made of an aluminum brazing sheet is interposed between the fins, 3 is a cylindrical header made of an aluminum brazing sheet that is temporarily attached to both ends of the flat tube 1 through the mounting holes 3a, and 4 is a cylindrical header made of an aluminum brazing sheet that is temporarily attached to both ends of the flat tube 1. This is a side plate made of an aluminum plate arranged on the outer surface of the straight pipe part 1a on one end side with small corrugated fins 5 made of an aluminum brazing sheet interposed therebetween.

Further, 6 is an unjoined assembly formed by combining the above-described flat tube 1, large corrugated fins 2, header 3, side plate 4, and small corrugated fins 5. And combination 6
Two flat surfaces 1b and 4a parallel to the straight tube portion 1a among the outer surfaces in FIG. 1 to FIG. A stainless steel rectangular jig plate 7 was applied to each of the parts 4a. In addition to a total of 15 circular flat surface gas escape holes 7a, each of these jig plates 7 has:
A total of five circular header joint gas escape holes 7b are provided in a row at positions corresponding to the outer surface side of the assembly 6 on the edge of the attachment hole 3a in the header 3.

After applying the two jig plates 7, the assembly 6 was temporarily fixed by tightening the two jig plates 7 with two tightening bands 8 made of band steel. At this time, the jig plate 7 on the upper surface side is in contact with the peripheral wall surface of the upper header 3 as shown in FIG. 2, while the jig plate 7 on the lower surface side is in contact with the peripheral wall surface of the upper header 3 as shown in FIG. It is slightly separated from the peripheral wall surface of No.3.

Next, the temporarily fixed assembly 6 is placed in an electric furnace for vacuum brazing in the state shown in FIG. A heat exchanger was obtained by joining each end of the large and small corrugated fins 2 and 5, the small corrugated fin 5, and the side plate 4 to each header 3, respectively.

For a large number of heat exchangers manufactured as described above, the rate of defective joints at the joints between the ends of the flat tubes 1 and the headers 3 was determined to be 1.0%. This value is one-seventh of the value of 7.0% for the heat exchanger manufactured by the conventional method described above.

Effects of the Invention In the method for manufacturing a heat exchanger according to the present invention, at least one of the pair of jig plates is in contact with the header or has a smaller distance from the header, in addition to the flat surface gas relief hole. Furthermore, a header joint gas release hole is provided at a position corresponding to the outer surface side of the assembly among the edges of the mounting holes in the header, and vacuum brazing is performed using these jig plates. It is something to do.

Therefore, according to this method, the connection between the jig plate and the part of the edge of the attachment hole in the header, which is the joining point between the end of the flat tube and the header, which is on the outside surface of the assembly, which has conventionally occurred, can be avoided. This eliminates the gas accumulation that had occurred between the two, making it possible to avoid bonding defects at the same bonding location.

In addition, according to this method, the jig plate is provided with a gas release hole at the header joint, and the area of the jig plate is smaller than that of the conventional one, so there is no need for the jig plate to be used during vacuum brazing. It is possible to quickly raise the temperature at the point where the header and flat tube are to be joined to a predetermined temperature without losing heat, and by saving thermal energy, it is possible to lower the cost of the product than in the past.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a heat exchanger manufactured by the method of the present invention before being charged into a vacuum brazing furnace, FIG. FIG. 3 is an enlarged vertical sectional view of the main part in FIG. 1. FIG. 4 is a perspective view showing the state of a heat exchanger manufactured by a conventional method before being charged into a vacuum brazing furnace, and FIGS.
It is an enlarged front view of the main part in a figure. 1... Flat tube, 1a... Straight pipe section, 1b... Flat surface, 2... Corrugated fin, 3... Header,
3a...Mounting hole, 4...Side plate,
4a... Flat surface, 6... Combination body, 7... Jig plate, 7a... Flat surface gas escape hole, 7b...
Header joint gas relief hole.

Claims (1)

[Claims] 1. At least a serpentine flat tube 1 having a plurality of flow paths inside and straight tube portions 1a parallel to each other, and a corrugated fin 2 interposed between adjacent straight tube portions 1a, Flat tube 1
Two flat surfaces 1b and 4a that are parallel to the straight pipe section 1a among the outer surfaces of the unjoined assembly 6 formed by combining the headers 3 which are temporarily attached to both ends of the headers 3 through the mounting holes 3a, are provided with a large number of flat surface gas release holes. A pair of jig plates 7 provided with holes 7a are applied, and then the combination body 6 is temporarily fixed by tightening the combination body 6 through both jig plates 7 with a tightening band 8, and predetermined parts of the combination body 6 are joined by vacuum brazing. A method of manufacturing a heat exchanger by providing a flat surface gas release on at least one of the pair of jig plates 7 that is in contact with the header 3 or has a smaller distance from the header 3. In addition to the hole 7a, a header joint gas escape hole 7b is provided at a position corresponding to the outer surface side of the assembly 6 among the edges of the attachment hole 3a in the header 3, and these jig plates 7 are 1. A method for manufacturing a heat exchanger, characterized in that vacuum brazing is carried out using vacuum brazing.