JPS6380194A - Heat exchanger - Google Patents

Abstract

PURPOSE:To prevent the development of voids at a joint section made by brazing between a tube and an end plate by forming an air escape passage on at least either one of the opposing faces of the tube and the burring section, the passage extending in the lengthwise direction of the tube. CONSTITUTION:In manufacturing a heat exchanger for a hot water tube room heater for automobiles a tube 105 is provisionally inserted into the burring section 102 of an end plate 101. Then after this insertion the end section is immersed into a solder bath, and the solder material intrudes into the gap between the tube 105 and the burring section 102 by the capillary section. This solder material intrudes from the end section in the lengthwise direction of the tube, and during this intrusion the air staying in the groove section 104 of the tube 105 escapes through a passage 103 to the outside. Consequently there are no voids developed between the burring section 102 and the tube 105.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to heat exchange, and can be used, for example, as a heater core of a hot water heating device for an automobile (a heater device for an automobile).

[Conventional technology]

FIG. 5 is a partially sectional view showing a conventionally known heat exchanger.

A wavy bent fin 520 is arranged between the plurality of tubes 505 arranged in parallel. A tank 521 is disposed at both ends of this tube 505 (only one end is shown in FIG. 5).
and the plurality of tubes 505 are connected by an end plate 501.

In such a heat exchanger, the tank 521 . The fluid to be heat exchanged (high temperature engine cooling water) flows in and is distributed from this tank 521 to each tube 505 . When the high-temperature heat exchange fluid flows through the tubes 505, it exchanges heat with the air flowing between the tubes 505, increasing the temperature of the air. This relatively high-temperature air is then blown into the vehicle interior.

After passing through the tube 505, the heat exchange fluid collects in the lower tank 521, and then returns to the engine (not shown).

In such a heat exchanger, in order to agitate the fluid flowing inside the tube 505 and improve heat transfer performance, it is known to form a recessed part in the tube 505 that protrudes from the outer surface toward the inner surface. .

FIG. 6 shows a heat exchanger in which a plurality of recesses 504 are formed in a tube 505 and an end plate 50.
FIG. 7 is a longitudinal cross-sectional view of the connection between the tube 505 and the end plate 501 and the sheath portion, and FIG. 8 is a cross-sectional view taken along the line -■ in FIG. 7. As shown in FIGS. 6 to 8, the end plate 501 has a tube 5.
The insertion hole 501a for inserting the tube 504
The number of holes is the same as the number of holes. A cylindrical burring portion 503 is formed around this insertion hole 501a.

The burring portion 503 is formed from the tube side toward the tank 521 side as shown in FIG. 7, or is formed on the side opposite to the tank 521.

The end of the tube 505 is inserted into the insertion hole 501a having the burring portion 503, and the space between the outer surface 505a of the tube 505 and the inner surface of the insertion hole 501a is filled with solder 506, whereby the end plate 501 and the tube 505 is being connected. In addition, solder 506
After inserting the tip of the tube 501 into the insertion hole 501a, this insertion connection part is immersed in a solder bath, and the molten solder spreads between the outer surface 505a of the tube 505 and the inner wall surface of the insertion hole 501a. It spreads throughout the gap due to capillary action.

[Problem that the invention seeks to solve]

If the recessed part 504 formed in the tube 505 is located at a position facing the burring part 503, voids (bubbles) 510 are generated between the recessed part 504 and the inner wall of the insertion hole 501a. There's a problem.

That is, the solder 506 that connects the tube 505 and the end plate 501 as described above spreads through the minute gap between them at a relatively high speed due to capillary action. Therefore, before the air in the space formed between the hollow part 504 and the inner wall of the insertion hole 501 can properly escape, the solder 506 enters around it.
As a result, a void 510 is formed between the two.

If a void 510 is formed in the joint between the end plate 501 and the tube 505, the strength of the joint between the tube 505 and the end plate 501 may deteriorate, or the corrosion resistance of this joint may deteriorate. There is a possibility that a problem may arise in which the fluid to be heat exchanged in the tank section leaks out.

[Means for solving problems]

In view of the above-mentioned conventional problems, the present invention aims to prevent the occurrence of voids at the joint between the tube and the end plate, thereby improving the joint strength between the two and preventing leakage of the fluid to be heat exchanged. The purpose is to prevent problems from occurring. In order to achieve this object, in the present invention, an air escape passage extending in the longitudinal direction of the tube is formed on at least one of the opposing surfaces of the tube and the burring portion.

[Action and effect]

Even if the solder spreads between the outer surface of the tube and the inner wall of the burring part of the end plate at a relatively high speed, the air stagnant between the two is released to the outside through the air release passage before the solder spreads. released. Therefore, even if the hollow part of the tube is located at a position facing the burring part, it is possible to prevent voids from occurring at that position. Therefore, there is no deterioration in the joint strength between the tube and the end plate, and there is no problem of leakage of the fluid to be heat exchanged in the tank from the joint.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings. 1st
The figure is a sectional view showing an embodiment of the present invention corresponding to the above-mentioned FIG. 7, FIG. 2 is a sectional view taken along the line nn in FIG. 1, and FIG. be.

A plurality of depressions 104 protruding from the outer surface toward the inner surface of the tube 105 having a flat shape are formed at regular intervals. In this embodiment, the thickness of the tube 105 is 0.13N, and the amount of inward protrusion of the recess 104 is 0.4 mm.

Although it is not clearly shown in these figures, this flat tube 105 is formed into an annular shape by bending a single band-shaped plate into a flat shape, making a so-called seam at the end, and welding the seam. They are forced to do so.

The end plate 101 has the same number of insertion holes 101a as the plurality of tubes 105.
A cylindrical burring portion 102 is formed at the opening edge of 01a.

This burring portion 102 is formed to extend from the tube 105 side toward the tank side.

The inner wall surface of this burring portion 102, that is, the surface facing the tube 105, has a width of about 2.5 mm.

An air escape passage, which is a rectangular groove with a depth of about 0.3 to 0.4 cages, is formed along the length of the tube 105. Two air escape passages are formed on each parallel surface of the flat burring part, and the air escape passages are formed at positions opposite to the depressions 104 formed in the tube 105. In addition, the burring part 10
2 may extend from the tank side to the tube 105 side.

There is a gap of approximately 0.1 to 0.2 between the inner wall surface of the burring portion 102 where the air escape passage 103 is not formed and the outer surface of the tube 105 where the recessed portion 104 is not formed.
A gap of tm is formed in which the brazing material 10
6 enters and fixes, thereby joining the two.

FIG. 3 shows the tube 105 and burring part 102 described above.
It is a cross-sectional view showing the joint part with the burring part 1.
02 is shown in the opposite direction to that shown in FIGS. 1 and 2 described above. The joining method using the brazing material 106 will be explained based on FIG. 3. First, the tube 105 is temporarily inserted into the burring 102 of the end plate 101. After inserting the tube, the end thereof is poured into a solder bath, and the gap between the tube 105 and the burring 102 is filled with the brazing material 1 by capillary action.
06 invades. At this time, as shown by the arrow R in FIG. When the brazing filler metal 106 enters, it is pushed out and released to the outside. Therefore, even if the brazing filler metal 106 enters at a high speed, the remaining air is effectively discharged to the outside, and no voids are generated between the burring portion 102 and the tube 105.

Note that in this embodiment, the air escape passage 103 is connected to the end plate 101.
Although the relief grooves are formed on the inner surface of the burring portion 102, for example, as shown in FIG. 4, relief grooves may be formed on the outer surface of the chirve 105.

Further, as shown in FIG. 9, the air escaping effect can be further improved by forming the air escaping passage 103 on both the outer surface of the duplex 105 and the inner wall surface of the burring portion 102.

In the above-described embodiments, the air escape passage is a square groove with a square cross section, but it is not limited to this square groove. For example, as shown in FIG. It may be configured to have a circular groove shape 103a or a triangular groove 103b having a triangular cross section, but is not particularly limited to this shape.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a sectional view thereof, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a tube and burring portion. 4 is a sectional view showing a second embodiment of the present invention, FIG. 5 is a partial sectional view showing a conventionally known heat exchanger, and FIG. 6 is a sectional view showing a conventional heat exchanger. FIG. 7 is a sectional view of the connecting portion shown in FIG. 6, FIG. 8 is a sectional view taken along the line ■-■ of FIG. 7, and FIG. FIG. 10 is a sectional view showing another example of application of the present invention. 101... End plate, 102... Burring part, 103
... Air relief passage, 104 ... Recessed part, 105 ...
·tube.

Claims (1)

[Scope of Claims] A plurality of tubes having a plurality of recesses protruding from the outer surface toward the inner surface, through which a fluid to be heat exchanged flows; a tank for storing exchange fluid; and an end plate for connecting the tube and the tank; the end plate has an insertion hole having a cylindrical burring portion for inserting and fixing the tube. A heat exchanger, wherein an air escape passage extending in the longitudinal direction of the tube is formed on at least one of opposing surfaces of the tube and the burring portion.