JPH0451252B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for joining heat exchange tubes and header plates in heat exchangers used in oil coolers, radiators, intercoolers for superchargers, and the like.

Prior art and its problems The conventional method of joining heat exchange tubes and header plates in heat exchangers involves the steps of drilling a hole in the header plate that is larger than the cross section of the heat exchange tube, and inserting the heat exchange tube into this hole. The method includes the following steps: expanding the heat exchange tube to bring the outer circumferential surface of the heat exchange tube into close contact with the inner circumferential surface of the hole; and brazing the heat exchange tube and the header plate. However, when a flat tube made of extruded aluminum material with multiple fluid passages arranged in parallel is used as a heat exchange tube, there are multiple partition walls inside the flat tube, so it is difficult to expand the heat exchange tube. The problem was that it was technically difficult and expensive. Also,
There was a problem in that a fillet of sufficient size was not formed between the outer peripheral surface of the flat tube and the area around the hole in the header plate, resulting in insufficient brazing strength. An object of the present invention is to provide a method for joining heat exchange tubes and header plates in a heat exchanger that solves the above problems.

Means for Solving the Problems The method of joining the heat exchange tube and header plate in the heat exchanger according to the present invention includes the steps of drilling a hole in the header plate that is smaller than the cross section of the heat exchange tube, and burring around the hole. Processing to make the size of the hole larger than the cross section of the heat exchange tube, forming a flange around the hole, inserting the heat exchange tube into the hole, and forming the sloped part of the header plate. A step of deforming the flange so that the angle of inclination becomes small and maintaining the inclination state, and also deforming the flange to bring the inner circumferential surface of the flange and the outer circumferential surface of the heat exchange tube into close contact, and brazing the header plate and the heat exchange tube. It consists of a process.

Embodiment FIG. 2 shows a heat exchanger in which heat exchange tubes and header plates are joined by the method of the present invention. This heat exchanger 1 is arranged in parallel between a pair of header plates 2 made of aluminum brazing sheets facing each other and arranged vertically at a predetermined interval, and both header plates 2, and both upper and lower ends are connected to the header plates 2, respectively. The joined flat heat exchange tubes 3 made of extruded aluminum and the aluminum brazing tubes 3 placed between adjacent flat heat exchange tubes 3 and brazed to the heat exchange tubes 3.
It consists of a sheet corrugated fin 4 and an aluminum header tank component 5 which is brazed to the outer surface of the upper and lower header plates 2, respectively. A groove 6 into which the end of the peripheral wall of the header tank component 5 is fitted is provided on the outer circumferential edge of the header plate 2 . A plurality of fluid passages 7 are provided in parallel in the heat exchange tube 3.

A method of joining the heat exchange tubes 3 and header plates 2 in the heat exchanger 1 is shown in FIGS. 1A to 1C.

When joining the heat exchange tubes 3 and the header plate 2, first a hole 10 smaller than the cross section of the heat exchange tube 3 is bored in the header plate 2. After that, burring is performed around the hole 10, and the hole 10 is
is made larger than the cross section of the heat exchange tube 3, and a flange 11 is formed around the hole 10 to protrude upward. At the same time, a portion of the header plate 2 around the flange 11 is bent obliquely upward to form an inclined portion 12 (see Fig. 1A
reference). Then, the end of the heat exchange tube 3 is inserted into the header plate 2. Next, the inclined portion 12 is pressed down by a press and deformed so that the inclination angle becomes small and the inclined state is maintained, and the flange 11 is also deformed (see FIG. 1B), and the inner circumferential surface of the flange 11 is heated. Temporarily fasten both by bringing them into close contact with the outer peripheral surface of the exchange tube 3 (see FIG. 1C). The deformation of the inclined portion 12 by pressing is performed using the upper mold 13 and lower mold 14 shown in FIGS. 1B and 1C. A recess 15 for accommodating the end of the heat exchange tube 3 is provided on the lower surface of the upper die 13, and a tapered surface 16 is provided at the inner peripheral edge of the lower end opening of the recess 15. Then, the tapered surface 16 comes into contact with the inclined portion 12 and deforms the inclined portion 12. Furthermore, the other end of the heat exchange tube 3 is temporarily fixed to another header plate 2 with the header plate 2 turned upside down.
Finally, the corrugated fins 4 are arranged between the adjacent heat exchange tubes 3, and the header tank component 5 is arranged, and the heat exchange tubes 3 and the header plate 2, the heat exchange tubes 3 and the corrugated fins 4, and the header plate are arranged. 2 and header tank component 5
and are brazed at the same time. At this time, the molten brazing filler metal accumulates at the corner between the lower surface of the inclined upper end of the inclined portion 12 and the periphery of the heat exchange tube 3, and a fillet of sufficient size is formed there. Therefore, the brazing strength between the header plate 2 and the heat exchange tube 3 increases.

In the above embodiment, the method of the present invention is applied to joining a flat heat exchange tube and a header plate, but the method of the present invention is also applied to joining a cylindrical heat exchange tube and a header plate. It is also applicable to Further, in the above embodiment, the header plate is made of an aluminum brazing sheet, but the heat exchange tube may be made of a brazing sheet instead. Furthermore, neither the header plate nor the heat exchange tubes need be made of brazing sheets.

Effects of the Invention According to the method of the present invention, there is no need to expand the heat exchange tube when joining the heat exchange tube and the header plate. Therefore, it becomes possible to join the header plate to the flat heat exchange tube provided with a plurality of fluid passages much more easily than in the conventional method, and the cost is also reduced. In addition, during brazing between the header plate and the heat exchange tube, molten brazing material accumulates at the corner between the lower surface of the upper end of the slope after deformation and the periphery of the heat exchange tube. A fillet of sufficient size is formed. Therefore, the brazing strength between the header plate and the heat exchange tube increases.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the method of the invention;
Figure A is a partial cross-sectional view of the state after burring has been performed around the hole drilled in the header plate.
Figure B is a partial cross-sectional view of the upper and lower molds used to temporarily fasten the header plate and the heat exchange tube, and Figure 1 C is the state where the inner peripheral surface of the flange is in close contact with the outer peripheral surface of the heat exchange tube. FIG. Second
This figure is a partially cutaway perspective view showing a part of a heat exchanger in which heat exchange tubes and header plates are joined by the method shown in FIG. 1. 2... Header plate, 3... Heat exchange tube, 10...
Hole, 11...flange, 12...slanted part.

Claims (1)

[Claims] 1. A step of drilling a hole 10 smaller than the cross section of the heat exchange tube 3 in the header plate 2, and performing a burring process around this hole 10 to make the size of the hole 10 larger than the cross section of the heat exchange tube 3. At the same time, a step of forming a flange 11 around the hole 10, a step of bending the portion of the header plate 2 around the flange 11 diagonally upward to form an inclined portion 12, and inserting the heat exchange tube 3 into the hole 10 are performed. The process involves deforming the inclined portion 12 of the header plate 2 so that its angle of inclination becomes small and maintaining the inclined state, and also deforming the flange 11 to bring the inner circumferential surface of the flange 11 and the outer circumferential surface of the heat exchange tube 3 into close contact. the header plate 2 and heat exchange tube 3
A method of joining a heat exchange tube and a header plate in a heat exchanger, which comprises a step of brazing the two.