JPS6222795Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a heat exchanger in which a large number of flat tubes are arranged in parallel, and both ends of the tubes are inserted into end plates and fixed by brazing.

For example, the heat exchanger 1 as shown in FIG. The vicinity is inserted into this insertion hole 3 and assembled, and the insertion portion is integrally brazed and fixed. Since this insertion part must be liquid-tight and withstand temperature changes and high liquid pressure, it must be firmly and reliably brazed. Therefore, the insertion part must be in contact with the insertion hole of the end plate and the outer surface of the flat tube with a uniform and small enough gap so that the molten brazing filler metal is evenly sucked in by capillary action. No. Incidentally, it is known that a brazed state in which a wide void is filled with a brazing material is relatively fragile.

Conventionally, for this reason, the insertion hole of the end plate was finished with precise dimensions to minimize the gap between it and the flat tube. However, since the flat tube is made of sheet metal, there is a limit to the improvement in the precision of its shape and dimensions, so assembling the heat exchanger by inserting the flat tube into the insertion hole is a process that requires a lot of effort and skill.
Furthermore, after assembly, the flat tube is expanded from the inside to improve contact with the insertion hole, but the contact between the flat tube and the insertion hole is still uneven and does not adhere well, resulting in poor brazing and strength. There was a shortage.

This idea was made in order to solve the above-mentioned drawbacks.The end plate was divided into two pieces A and B and stacked one on top of the other. A step is provided at the top and bottom of the flat tube, and the upper and lower surfaces of the flat tube are sandwiched between the upper and lower walls of the insertion holes of both end plates A and B, and the upper and lower surfaces of the flat tube are brought into uniform contact with each other, thereby achieving a strong and good brazed state. The structure is designed to facilitate the assembly process.

This invention will be explained with reference to embodiments shown in FIGS. 2 to 4. In FIG. 2, the cross-sectional shape of the flat tube 14 is shown, where W is the width of the outer surface and h is the height of the outer surface. The end of this flat tube 14 is inserted into the insertion hole 13 of the end plate 12 and fixed to form a heat exchanger. The end plate 12 is made by overlapping end plates A and B and brazing them together. The insertion hole 23 of the end plate A has a width w and a vertical length h', where h' is slightly larger than the height h of the flat tube, and h'=h+c (for example, h
= 4 mm, h' = 5 mm). The upper wall 23u of the insertion hole 23 is at the same height as the upper wall 13u of the insertion hole 13 of the end plate 12, and the lower wall 23l is located below the lower wall 13l of the insertion hole 13 by c. Further, the upper side Au of the end plate A is at the same height as the upper side 12u of the end plate 12, and the lower side Al is slightly smaller than the position of the lower side 12l of the end plate 12, e.g.
It is shortened by 0.5mm and positioned slightly above. The end plate B has a vertically symmetrical shape with the end plate A, and its insertion hole 33 is similar to the insertion hole 13 of the end plate 12.
The lower wall 13l and the lower wall 33l are at the same height, the upper wall 33u is located above the upper wall 13u by c, and its vertical length is h'=h+c. Also, the lower side Bl of the end plate B is the lower side 12l of the end plate 12.
The top side Bu is at the same height as the top side 12u.
It is located at a position lower than that by a slight dimension d. End plate B can be obtained by turning the same shape as end plate A upside down.

To assemble the end plates A and B and the flat tube 14, first, as shown in FIG. Assemble by inserting the two end plates A and B together. Next, as shown in FIG. 4, the above assembly is placed on a brazing table 41, and the inner and outer surfaces of the end plates A and B are sandwiched between the jigs 42 and 43.
When the weights 44 are placed on the upper sides of the end plates A and B, the end plates A and B are crimped together via the solder foil 40, and the end plates A and B are slightly shifted vertically to form the flat tube 1.
4 upper surface 14u and the insertion hole upper surface 23u of end plate A,
The lower surface 14l of the flat tube and the lower surface 33l of the insertion hole of the end plate B are crimped so as to be sandwiched from above and below. At this time, there is a step on the upper and lower sides of the end plates A and B by a small dimension d, so the weight 4
4, whose total weight is the flat tube upper and lower surfaces 14u, 1
Acts on 4l clamping. As long as the load by the weight 44 effectively acts on the upper and lower surface crimping portions of the flat tube 14, the step d on the upper and lower sides of the end plate
may be less than d→o. When this is heated in a brazing furnace, the crimped parts between the A and B end plates and between the insertion hole and the flat tube suck the molten brazing material by capillary action, which is caused by the step inside the insertion hole. The void having the dimension c is also filled with the brazing material and fixed by brazing. Note that heat transfer fins may be simultaneously fixed to the inner or outer surface of the flat tube 14 by integral brazing.

As mentioned above, whereas conventionally a single end plate had an insertion hole with a shape that was almost the same as the cross-sectional shape of the flat tube and the flat tube was inserted therethrough, slightly larger insertion holes were provided at the top and bottom of the tube. The structure is such that the two end plates are overlapped and shifted, and the upper and lower surfaces of the flat tube are sandwiched and crimped from above and below, resulting in uniform and close contact, ensuring capillary action at the crimping part, and brazing. It has a structure that allows for strong brazing with no defects. Furthermore, when assembling the heat exchanger, the insertion hole is larger than the flat tube, so it can be easily assembled.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a heat exchanger, and FIG. 2 is a drawing of an embodiment showing the constituent members of the heat exchanger of the present invention. FIG. 3 is a cross-sectional view showing the flat tube inserted into the heat exchanger according to the embodiment of the present invention, and FIG. 4 is a cross-sectional view showing the relative positions of the end plate and the flat tube according to the embodiment of the present invention in a fixed state. 2, 12, A, B... end plate, 4, 14... flat tube, 3, 13, 23, 33... insertion hole.

Claims (1)

[Scope of utility model registration request] In a heat exchanger in which a large number of flat tubes are arranged side by side and both ends are inserted into insertion holes drilled in the end plate and fixed, the vertical dimension is slightly larger than the vertical external dimension of the flat tube whose upper and lower surfaces are flat. The two end plates A and B, each having an insertion hole, are stacked one on top of the other, and the end of the flat tube is inserted into the tube. , the upper wall surface or lower wall surface of the insertion hole of each end plate B is brought into close contact with the upper surface or lower surface of the tube,
A heat exchanger having two joined end plates, characterized in that the A and B end plates and the ends of the flat tube are integrally brazed and fixed.