JP2003065687A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To employ a welded tube as a tube in a radiator wherein the tube is mechanically connected to a fin through expanding. SOLUTION: A welded part 111a is provided at a site deviated from curved parts 111b easily generating a stress concentration. By this method, the generation of an excessive stress in the welded part 111a upon expanding can be restrained. Accordingly, a stress generated in the welded part 111a upon expanding is prevented from becoming larger than the bearing force (allowable stress) of the welded part 111a even when the welded part 111a is softened upon welding and the bearing force (mechanical strength) is deteriorated whereby the welded tube can be employed for the radiator in which the tube 111 is mechanically connected to the fin 112 through expanding. As a result, the manufacturing cost of the tube 111 is reduced compared with a case wherein a seamless tube is employed for the tube 111.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to plastically deform a tube so as to increase its cross-sectional area (hereinafter, referred to as
This act is called expansion. ), And a heat exchanger in which tubes and fins are mechanically joined.

[0002]

2. Description of the Related Art In a heat exchanger in which a tube and a fin are mechanically joined, since the tube is plastically deformed so as to expand the cross-sectional area of the tube by expansion, the elongation of the tube material is relatively large, and It requires proof stress against elongation of material. Therefore, in the past (for example, Japanese Patent Laid-Open No. 2000-
No. 74589) employs a seamless tube manufactured by seamless drawing or extrusion as a tube for expansion.

[0003]

By the way, since the seamless pipe has a larger manufacturing man-hour (manufacturing cost) than a welded pipe (a pipe joined by welding after bending a plate material into a tubular shape), the seamless pipe is The manufacturing cost is higher than that of welded pipe.

Therefore, the inventors have considered using a welded pipe in place of a seamless pipe in a heat exchanger for mechanically joining a tube and a plate fin. It is difficult to simply adopt a welded pipe in place of a seamless pipe, because it is softened by the heat of time as compared with the material (a part other than the welded part) and the proof stress (mechanical strength) of the welded part is reduced.

In view of the above points, the present invention has an object to mechanically join a tube and a fin by expanding the tube even in a welded tube.

[0006]

In order to achieve the above-mentioned object, the present invention provides a tube (111) through which a fluid flows, and a fluid flowing through the tube (111) according to the invention of claim 1. The tube (111) has a fin (112) that promotes heat exchange with a fluid flowing outside the tube (111), and the tube (111) is inserted through an insertion hole (112a) provided in the fin (112). (111)
A heat exchanger in which the tube (111) and the fins (112) are mechanically joined by plastically deforming the tube (111) so as to increase the cross-sectional area of the tube (11).
1) is a welded pipe in which a plate material is bent into a flat tubular shape and then joined by welding. Further, a welded portion (111a) of the tube (111) is a curved portion (111b) formed at an end in the major axis direction. ) Is provided in a portion deviated from.

As a result, since the welded portion (111a) is provided at a portion deviated from the curved portion (111b) where stress concentration is likely to occur, the welded portion (111a) is expanded during pipe expansion.
It is possible to suppress the occurrence of excessive stress in the.

Therefore, during welding, the welded portion (111a)
Even if the strength of the welded part (111a) is reduced when the pipe is softened and the proof stress (mechanical strength) is reduced,
Since it is possible to prevent the yield strength (allowable stress) of a) from being exceeded, a welded tube can be adopted in the heat exchanger in which the tube (111) and the fin (112) are mechanically joined by expanding the tube. In addition, the manufacturing cost of the tube 111 can be reduced as compared with the case where the seamless tube is adopted as the tube (111).

According to the second aspect of the invention, the welded portion (11
1a) is provided at a portion corresponding to a substantially central portion in the major axis direction.

As a result, the stress generated in the welded portion (111a) can be reliably reduced, so that the reliability of the tube (111) can be further improved.

In the third aspect of the invention, the insertion hole (11
The edge portion of 2a) is characterized in that a recessed portion (112d) that is depressed in the build-up direction of the welded portion (111a) is provided at a portion corresponding to the welded portion (111a).

As a result, the recess (112d) functions as an escape means for alleviating the interference between the build-up and the insertion hole (112a), so that the tube (11) is provided near the build-up.
The gap generated between 1) and the fin 112 is smaller than that in the case where the recess 112d is not provided.

Therefore, it is possible to prevent the contact area (heat conduction) between the tube (111) and the fins (112) from becoming small, so that it is possible to prevent the heat exchange capacity of the heat exchanger from decreasing.

According to the fourth aspect of the invention, the tube (111) through which the fluid flows, and the fin (for promoting heat exchange between the fluid flowing inside the tube (111) and the fluid flowing outside the tube (111) 112) with fins (1
12) The tube (1) is inserted into the insertion hole (112a) provided in
11) is a heat exchanger in which the tube (111) and the fins (112) are mechanically joined by plastically deforming the tube (111) so as to enlarge the cross-sectional area of the tube (111). There is a tube (111)
Is a welded pipe obtained by bending a plate material into a tubular shape and then joining them by welding. The welded portion (1) is included in the edge portion of the insertion hole (112a).
11a) is provided with a recess (112d) that is depressed in the buildup direction of the welded portion (111a).

As a result, the recess (112d) functions as an escape means for alleviating the interference between the buildup and the insertion hole (112a), so that the tube (11) near the buildup.
The gap generated between 1) and the fin 112 is smaller than that in the case where the recess 112d is not provided.

Therefore, it is possible to prevent the contact area (heat conduction) between the tube (111) and the fin (112) from becoming small, so that it is possible to prevent the heat exchange capacity of the heat exchanger from decreasing.

The present invention is not limited to the flat tube, but can be applied to other shapes such as a circular tube.

According to a fifth aspect of the present invention, there is provided the heat exchanger manufacturing method according to any one of the first to fourth aspects, wherein the tube expanding jig (200) expands the tube (111).
Among the above, a slit (21) for avoiding interference with the buildup is provided at a portion of the welded portion (111a) corresponding to the buildup.
0) is provided, the slit width (D) of the slit (210) is made larger than the buildup width (d) of the welded portion (111a), and the slit width (D) of the pipe expanding jig (200) is The ratio (D / A) of the slit width (D) to the dimension (A) of the portion parallel to D) is 0.32 or less,
Furthermore, the tube (111) is expanded by the pipe expanding jig (200).
Plastic deformation of the tube (111) and fin (11
2) A method for manufacturing a heat exchanger characterized by mechanically joining and.

As a result, as shown in FIG. 17, which will be described later, the tube (111) and the fin (112) can be mechanically joined to each other without significantly reducing the heat dissipation ability.

Incidentally, the reference numerals in the parentheses of the above-mentioned means are examples showing the correspondence with the concrete means described in the embodiments described later.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment)
The heat exchanger according to the present invention is applied to a radiator that cools cooling water by exchanging heat between cooling water and air of an internal combustion engine (engine), and FIG. 1 shows a radiator 100 according to the present embodiment. It is a front view.

In FIG. 1, a tube 111 is a metal (aluminum in the present embodiment) tube through which cooling water flows, and the tube 111 has a flat cross section as shown in FIG. It is a welded pipe (electric resistance welded pipe) that is joined by welding after being formed into an oval) tubular shape.

Then, the welded portion 111a of the tube 111
Is provided at a portion (a portion between the two curved portions 111b) that is deviated from the curved portion 111b having the smallest radius of curvature formed at the end portion of the tube cross section in the major axis direction W (the portion between the two curved portions 111b) and its outer peripheral surface side (described later). On the side that comes into contact with the plate fin 112), the build-up (welding bead) by welding formed on the outer peripheral surface side is scraped off by a cutting (grinding) means such as a grinder to form a smooth curved surface.

Further, in FIG. 1, the fin 112 is a tube 1.
11 is made of a metal (aluminum in the present embodiment) that extends in a direction orthogonal to the longitudinal direction (vertical direction in FIG. 1) and extends in a strip shape in the minor axis direction T of the tube 111 to promote heat exchange of cooling water. It is a plate fin, and this fin 11
In FIG. 2, as shown in FIG. 3, the insertion hole 112a through which the tube 111 is inserted, and a part of the fin 112 are cut and raised in the shape of an armor window, and the air flowing around the fin 112 is turned to change the temperature boundary layer. Louver 112b with growth suppression
Are provided by press working or roller working.

In this embodiment, by forming the insertion hole 112a by burring, a wall surface is formed along the outer peripheral surface of the tube 111 at the outer edge of the insertion hole 112a as shown in FIGS. Burring portion 112c having
The tube 11 when the tube 111 is expanded and the fin 112 and the tube 111 are mechanically joined.
The contact area between 1 and the fin 112 is increased.

The tube 111, the fins 112, and the cooling water constitute the core portion 110 for exchanging heat with the cooling air, and the tube 111 has a major axis direction W flowing outside the tube 111. A plurality of fins 112 are arranged side by side in the longitudinal direction in a state of being arranged substantially parallel to the direction.

By the way, as shown in FIG. 1, header tanks 120 extending in a direction orthogonal to the longitudinal direction of the tubes 111 and communicating with a plurality of tubes 111 are joined to both ends of the tubes 111 in the longitudinal direction. As shown in FIGS. 4 and 5, the header tank 120 includes a core plate 121 made of metal (aluminum in the present embodiment) to which a plurality of tubes 111 are joined by expansion, and a core plate 121 inside the tank. The tank main body 122 is made of resin (nylon in this embodiment) that constitutes the space.

The header tank 120 on the upper side of FIG. 1 distributes and supplies cooling water to each tube 111.
The header tank 120 on the lower side of the drawing collectively collects the cooling water flowing out from each tube 111.

Here, the core plate 121 and the tank main body 122 are such that the caulking projections (claws) provided on the core plate 121 with the front end 122a of the tank main body 122 inserted into the groove 121a of the core plate 121.
The front end side of 121b is plastically deformed so as to be bent toward the tank main body 122 side, and thus caulked and fixed.

A packing 122b made of an elastic material such as rubber is provided at the bottom of the groove 121a to contact the skirt 122a and seal the gap between the tank body 122 and the core plate 121.

Further, the tube 111 and the core plate 12
In order to prevent the cooling water from leaking out from the gap with 1, the adhesive made of a thermosetting resin material,
Alternatively, it is firmly fixed by soldering to ensure a reliable seal. In addition,
In this embodiment, the adhesive or solder is used for sealing, but laser welding or the like may be used for welding.

Next, a method of expanding the tube 111 (a method of joining the tube 111 and the fin 112) will be described.

FIG. 6 (a) is a front view of the tube expanding jig 200, FIG. 6 (b) is a view taken in the direction of arrow A in FIG. 6 (a), and FIG.
FIG. 4 is a cross-sectional view showing a state in which a tube expanding jig 200 (hatched portion) is inserted into a tube 111.

Then, the pipe expanding jig 200 is attached to the tube 11.
The tube 111 is expanded by penetrating the inside of the tube 1 to mechanically join the fin 112 and the tube 111.

The welded portion 11 of the pipe expanding jig 200
A groove-like slit 210 for avoiding interference with the build-up (welding bead) is provided in a portion corresponding to the build-up (welding bead) of 1a, and a slit width D of this slit 210 (see FIG. 7). ) Is the ratio of the slit width D (chord length) to the arc length L corresponding to the slit 210 (D /
L) is approximately 1 (0.9 ≦ D / L).

Next, the function and effect of this embodiment will be described.

In the present embodiment, since the welded portion 111a is provided at a portion deviated from the curved portion 111b where stress concentration is likely to occur, it is possible to prevent excessive stress from being generated in the welded portion 111a during pipe expansion. Therefore, even if the welded portion 111a is softened at the time of welding and the proof stress (mechanical strength) is reduced, the stress generated in the welded portion 111a at the time of expanding the pipe is
Since it is possible to prevent the yield strength (allowable stress) of 11a from being exceeded, the heat exchanger in which the tube 111 and the fin 112 are mechanically joined by expansion (in the present embodiment, the radiator 10
A welded pipe can be adopted for 0). In addition, the manufacturing cost of the tube 111 can be reduced as compared with the case where the seamless tube is adopted as the tube 111.

Note that FIG. 8A is a numerical simulation of the stress generated at the time of pipe expansion, and FIG. 8B is an explanatory diagram showing the stress generation position. Then, as is clear from FIG. 8, a large stress is generated in the curved portion 111b,
In the portion deviated from the bending portion 111b, the bending portion 11
It can be seen that the stress is smaller than 1b.

(Second Embodiment) In the above-described embodiment, the build-up (welding bead) formed on the outer peripheral surface side of the tube 111 is scraped off, but in this embodiment, the tube 111 is removed.
The cutting process for scraping off the build-up (welding bead) formed on the outer peripheral surface side of the welding part is abolished, and as shown in FIG. 9, the welding part 111a is formed at a portion corresponding to the welding part 111a in the edge part of the insertion hole 112a. Recess 112 that is depressed in the buildup direction
d is provided.

Next, the function and effect of this embodiment will be described.

FIG. 10A is a view taken in the direction of arrow A in FIG. 9B, FIG. 10B is a sectional view taken along line BB in FIG. 9B,
FIG. 11 shows a case where the tube 111 is expanded without forming the recess 112d while leaving the buildup (welding bead) formed on the outer peripheral surface side of the tube 111.
2 (a) is a view on arrow A in FIG. 11 (b), and FIG.
11B is a sectional view taken along line BB of FIG. 11B.

As shown in FIGS. 11 and 12, when the tube 111 is expanded without forming the recess 112d,
Since the portion of the insertion hole 112a (burring portion 112c) corresponding to the build-up (welding bead) is plastically deformed so as to bulge, in the vicinity of the build-up (welding bead), the tube 111 and the fins 112 are relatively closed. A large gap will occur.

On the other hand, in this embodiment, the insertion hole 11
The welded portion 11 is attached to a portion of 2a corresponding to the welded portion 111a.
Since the concave portion 112d that is recessed in the build-up direction of 1a is provided, the concave portion 112d functions as an escape means that reduces interference between the welding bead and the insertion hole 112a (burring portion 112c). Therefore, the gap generated between the tube 111 and the fin 112 in the vicinity of the build-up (welding bead) is smaller than in the case where the recess 112d is not provided.

By extension, the tube 111 and the fin 112
Since it is possible to prevent the contact area (heat conduction) with the heat exchanger from decreasing, it is possible to prevent the heat exchange capacity of the heat exchanger (radiator) from decreasing.

In the present embodiment, the shape of the recess 112d is a rhombus (triangular pyramid), but the present embodiment is not limited to this and may be, for example, a dome shape (spherical shape). .

(Third Embodiment) In the above-described present embodiment,
The tube 111 was expanded by pushing the tube expansion jig 200 into the tube 111, but in the present embodiment, the tube expansion jig 200 is pulled out to penetrate the tube 11. Note that FIG. 13 is a view showing the pipe expanding jig 200 for pulling out.

(Fourth Embodiment) In the above-described embodiment, the welded portion 111a is provided at a portion deviated from the portion corresponding to the substantially central portion of the tube cross section in the major axis direction W. As shown in FIG. 15, the welded portion 111a is provided in a portion corresponding to the center of the cross section of the tube in the major axis direction W.

Incidentally, FIG. 14 shows an example in which this embodiment is applied to the first embodiment, and FIG. 15 shows an example in which this embodiment is applied to the second embodiment.

If the welded portion 111a is provided at a portion substantially corresponding to the central portion of the cross section of the tube in the major axis direction W, as shown in FIG.
As is clear from (a), since the stress generated in the welded portion 111a can be minimized, the tube 11
The reliability of No. 1 (welded pipe) can be further improved.

(Fifth Embodiment) This embodiment is a modification of the pipe expanding jig 200. Specifically, as shown in FIG. The slit width D of the slit 210 provided at the corresponding portion is made larger than the buildup width d (see FIG. 7) of the welded portion 111a (D> d), and is parallel to the slit width D of the external dimensions of the tube expanding jig 200. Dimensions of various parts, that is, tube expansion jig 2
The slit width D for the major axis dimension A of the cross-sectional dimension of 00
Ratio (= D / A) of 0.32 or less.

When the tube 111 is expanded using the tube expanding jig 200 having the slit 210, the portion of the tube 111 corresponding to the slit 210 is not expanded. Here, the ratio of the slit width D to the major axis dimension A (=
When D / A) increases, the gap between the unexpanded portion of the tube 111 and the opening edge of the insertion hole 112a increases, so that the contact area between the tube 111 and the fin 112 decreases.

FIG. 17 shows the test results showing the relationship between the ratio of the slit width D to the major axis dimension A (= D / A) and the heat exchange capacity (heat dissipation capacity) Qw of the radiator 100. Heat dissipation capacity Qw = 100. Indicates the heat dissipation capability when the fin 112 is joined to the seamless pipe without the welded portion 111a by expanding the pipe.

As is clear from FIG. 17, if the ratio of the slit width D to the major axis dimension A is 0.32 or less, it is possible to prevent the contact area between the tube 111 and the fin 112 from being greatly reduced. It can be made to be substantially equivalent to the heat dissipation capability of.

(Other Embodiments) In the above-described embodiments, the present invention is applied to the radiator, but the present invention is not limited to this and can be applied to other heat exchangers.

[Brief description of drawings]

FIG. 1 is a front view of a heat exchanger according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the tube according to the first embodiment of the present invention.

FIG. 3 is a front view showing a joint relationship between a tube and fins according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view taken along the line AA of FIG.

5 is a sectional view taken along line BB of FIG.

FIG. 6A is a front view of the tube expanding jig according to the first embodiment of the present invention, and FIG. 6B is a view taken along arrow A of FIG.

FIG. 7A is a cross-sectional view showing a state in which a tube expanding jig is inserted into the tube according to the first embodiment of the present invention,
(B) is an enlarged view of the slit.

FIG. 8A is a graph showing a stress generated at the time of pipe expansion, and FIG. 8B is an explanatory diagram showing a stress generation position.

9A is a cross-sectional view of a tube according to a second embodiment of the present invention, and FIG. 9B is an enlarged view of part A of FIG. 9A.

10 (a) is a view on arrow A of FIG. 9 (b),
9B is a sectional view taken along line BB of FIG. 9B.

11A is a cross-sectional view of a tube according to a comparative example, and FIG. 11B is an enlarged view of part A of FIG.

12 (a) is a view on arrow A of FIG. 11 (b),
11B is a sectional view taken along line BB of FIG. 11B.

13A is a front view of a tube expanding jig according to a third embodiment of the present invention, and FIG. 13B is a view taken in the direction of arrow A in FIG. 13A.

FIG. 14 is a front view showing a joint relationship between tubes and fins according to a fourth embodiment of the present invention.

FIG. 15 is a front view showing a joint relationship between tubes and fins according to a fourth embodiment of the present invention.

FIG. 16 is a sectional view of a pipe expanding jig according to a fifth embodiment of the present invention.

FIG. 17: Ratio of slit width D to major axis dimension A (= D
/ A) and the heat exchange capacity (heat dissipation capacity) Q of the radiator 100
It is a graph which shows the relationship with w.

[Explanation of symbols]

111 ... Tube, 111a ... Welded portion.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3L103 AA01 AA11 BB14 BB16 BB33                       BB39 BB42 BB43 CC02 CC09                       CC22 DD08 DD32 DD33 DD52

Claims (5)

[Claims] 1. A tube (111) in which a fluid flows, and fins (112) for promoting heat exchange between the fluid flowing in the tube (111) and the fluid flowing outside the tube (111). The insertion hole (112a) provided in the fin (112)
With the tube (111) inserted through the tube (111), the tube (111) is plastically deformed so as to increase the cross-sectional area of the tube (111).
1) is a heat exchanger in which the fins (112) are mechanically joined, and the tube (111) is a welded tube in which a plate material is bent into a flat tube and then joined by welding, , A welded portion (111a) of the tube (111)
Is provided at a portion deviated from the curved portion (111b) formed at the end in the major axis direction. 2. The heat exchanger according to claim 1, wherein the welded portion (111a) is provided at a portion corresponding to a substantially central portion in the major axis direction. 3. A recess (112d) that is depressed in the build-up direction of the weld (111a) at a portion of the edge of the insertion hole (112a) that corresponds to the weld (111a).
The heat exchanger according to claim 1, wherein the heat exchanger is provided. 4. A tube (111) in which a fluid flows, and fins (112) for promoting heat exchange between the fluid flowing in the tube (111) and the fluid flowing outside the tube (111). The insertion hole (112a) provided in the fin (112)
With the tube (111) inserted through the tube (111), the tube (111) is plastically deformed so as to increase the cross-sectional area of the tube (111).
1) is a heat exchanger in which the fins (112) are mechanically joined, and the tube (111) is a welded tube in which a plate material is bent into a tubular shape and then joined by welding, Of the edges of the hole (112a), the welded portion (11
1a) is provided with a recessed portion (112d) that is depressed in the buildup direction of the welded portion (111a), the heat exchanger. 5. The method for manufacturing a heat exchanger according to claim 1, wherein the tube expanding jig (200) expands the tube (111).
Of the above, a slit (2) for avoiding interference with the buildup is provided at a portion of the welded portion (111a) corresponding to the buildup.
10) is provided, and the slit width (D) of the slit (210) is set to the build-up width (d) of the welded portion (111a).
The ratio (D / A) of the slit width (D) to the dimension (A) of the outer dimension of the tube expanding jig (200) parallel to the slit width (D) is 0.32. The method is as follows, and further, the tube (111) is plastically deformed by the tube expanding jig (200) to mechanically join the tube (111) and the fins (112). .