JP2003106679A - Vessel for heat exchanger and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a degradation in airtightness between a joint flange 11 and another casing due to deformation of the joint flange 11 without using a reinforcement, in a vessel for a heat exchanger comprising a barrel part 10 and the joint flange 11 bend at an edge of the barrel part for another casing. SOLUTION: The joint flange 11 has a multifold structure having a bent flange portion 11a continuous with the barrel part 10, and a folded flange portion 11b folded on the bent flange portion, and the folded flange potion 11b has a contact potion 11c with the barrel part 10. The barrel part 10 bears an external force acting on the joint flange 11 via the contact portion 11c to prevent deformation of the joint flange 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can body for a heat exchanger incorporated in a water heater or the like and a method for manufacturing the can body.

[0002]

2. Description of the Related Art A heat exchanger can body of this type is provided with a body portion containing a heat-absorbing water pipe and a joint flange bent to an edge of the body portion for connecting to another casing such as a combustion casing, The heat exchanger can body and the other casing are caulked and joined together with the joint flange joined to the other casing.

Conventionally, the joining flange is composed of a simple bending flange continuous with the body. Here, since the can body is made of copper, such a simple bending flange is annealed in a brazing furnace, and the joining flange is likely to be deformed in a caulking process with another casing in the next process to maintain airtightness. Becomes difficult. Therefore, conventionally, a reinforcing material such as stainless steel is welded to the joint flange to prevent the joint flange from being deformed (see JP-A-6-11192 and JP-A-2000-18727).

Further, as shown in FIG. 9, the joint flange a
Is a double-folded structure having a bending flange portion a1 continuous to the body portion b and an overlapping flange portion a2 that is folded on the surface of the bending flange portion opposite to the body portion b, and the strength of the joining flange is increased. Is also conventionally known.

[0005]

When the reinforcing material is welded to the joining flange as in the former conventional example, the number of parts and the number of steps are increased and the cost is increased. Further, the joint flange a having the double bending structure as in the latter conventional example is weak against an external force from the lower part of the drawing, and the strength may be insufficient, resulting in insufficient airtightness.

By the way, the heat exchanger can body is manufactured by joining a pair of half-cylinder-shaped can body halves, and has a flat plate portion which becomes a body part in manufacturing each of the can body halves. After bending the joining flange on the side edge of the blank, a bending die composed of a punch and a die is used, and the blank is pushed into the die by the punch and bent into a half-split tube shape. Here, if the joint flange has the double-fold structure as described above, the resistance of the joint flange to the bending process of the blank becomes large, and bending failure and distortion of the joint flange are likely to occur.

In view of the above problems, it is a first object of the present invention to provide a heat exchanger can body capable of improving the strength of a joint flange as much as possible without using a reinforcing material. A second object of the present invention is to provide a method capable of favorably performing bending of a blank for manufacturing a half of a can body without causing defective bending or distortion of a joining flange.
It is an issue.

[0008]

SUMMARY OF THE INVENTION In order to solve the first problem described above, the present invention provides a can for a heat exchanger having a body portion and a joint flange bent to the edge of the body portion and joined to another casing. In the body, the joint flange has a double-folded structure having a bending flange portion continuous to the body portion and an overlapping flange portion folded on the bending flange portion, and a contact portion for the body portion is formed in the overlapping flange portion.

In order to solve the second problem,
A method for manufacturing a can body for a heat exchanger by joining a pair of can body halves in a half-split cylinder shape, wherein a side edge of a blank having a flat plate part to be a body part in manufacturing each can body half part. According to the present invention, in which after bending the joining flange of the double folding structure, using a bending die composed of a punch and a die, the blank is pushed into the die by the punch and bent into a half-split cylinder, A groove is formed in the die to receive the joint flange so as to sandwich the joint flange from both sides in the plate thickness direction, and the bending is performed in a state where the distortion of the joint flange is restricted by the groove.

According to the heat exchanger can body of the present invention, a part of the external force applied to the joint flange can be received by the body portion through the contact portion, and the strength is improved. In this case, the end edge of the overlapping flange portion may be used as a contact portion and may be brought into contact with the body portion, but if the end of the overlapping flange portion is bent along the body portion to form the contact portion, the body portion is formed. The contact area with respect to is increased, and the strength is further improved. Furthermore, if the contact portion is joined to the body portion, the strength of the joint flange is dramatically improved.

Further, even if the overlapping flange portion is folded on the surface of the bending flange portion opposite to the body portion and the end of the overlapping flange portion is bent along the inner wall surface of the body portion to form the contact portion. This is good, but if a gap is created between the body and the contact, moisture and the like in the combustion exhaust will condense and accumulate there, causing easy corrosion and poor durability. On the other hand, if the overlapping flange portion is folded on the body-side surface of the bending flange portion and the contact portion is brought into contact with the outer wall surface of the body portion, even if a gap is formed between the body portion and the contact portion. Water does not collect there, improving durability.

Further, according to the method of the present invention, by forming the joint flange into a double-fold structure, even if the resistance of the joint flange to the bending work of the blank increases, the joint flange is formed in the plate thickness direction by the groove portion of the die. It can be bent without distortion and can be bent well.

[0013]

1 shows a heat exchanger incorporated in a water heater. This heat exchanger is configured by accommodating a heat absorbing water pipe (not shown) having a large number of heat exchange fins 2 in a copper can body 1 having a rectangular tube-shaped body portion 10.
The water supply communication pipe 3 is wound around the outer periphery of the lower half of the, the water supply communication pipe 3 is connected to the upstream end of the endothermic water pipe, and the hot water supply pipe 4 is connected to the downstream end of the endothermic water pipe.

A lower flange 11 serving as a joint flange for another casing (not shown), which is another casing, is bent at the lower end edge of the body portion 10, and the can body 1 has the lower flange 1.
At 1, it is caulked to the combustion housing. Also, the body 10
The flange plate 13 is spot-welded to the upper flange 12 bent at the upper end edge of the, and the exhaust casing is caulked to the can body 1 at this flange plate 13.

The lower flange 11 is, as shown in FIG.
It has a double folding structure having a bending flange portion 11a continuous to the body portion 10 and an overlapping flange portion 11b folded and overlapped with the bending flange portion 11a.
A contact portion 11c for 0 is formed. In the structure shown in FIG. 2, the overlapping flange portion 11b is replaced with the bending flange portion 11a.
The contact portion 11c is formed by folding the end portion of the overlapping flange portion 11b along the outer wall surface of the body portion 10 by folding it on the surface of the body portion 10 side.

As shown in FIG. 3, the overlapping flange portion 11
b may be folded on the surface of the bending flange portion 11a opposite to the body portion 10, and the end of the overlapping flange portion 11b may be bent along the inner wall surface of the body portion 10 to form the contact portion 11c. Further, as shown in FIG. 4, the overlapping flange portion 11b is folded over the surface of the bending flange portion 11a on the body portion 10 side so that the edge of the overlapping flange portion 11b contacts the outer wall surface of the body portion 10, and the overlapping flange portion 11b is formed. The edge of the portion 11b is connected to the contact portion 11c
Also good.

In any of FIGS. 2 to 4, 2
The double-folded structure enhances the rigidity of the lower flange 11, and a part of the external force applied to the lower flange 11 can be received by the body 10 via the contact portion 11c.
The strength of the lower flange 11 is improved. Therefore, without attaching a reinforcing member as in the conventional example, the lower flange 11 is prevented from being deformed in the caulking process of the combustion housing, and the airtightness is maintained.

Further, as in the embodiment of FIGS. 2 and 3, the end of the overlapping flange portion 11b is bent so that the strip-shaped contact portion 11 is formed.
If c is formed, the contact area with the body portion 10 is increased and the strength of the lower flange portion 11 is further improved. In addition, in the embodiment of FIG. 3, since the contact portion 11c is located on the inner wall surface side of the body portion 10, if a gap is created between the body portion 10 and the contact portion 11c, condensed water such as moisture in combustion exhaust gas is generated. Will accumulate in this gap and will easily corrode. On the other hand, in the embodiment of FIGS. 2 and 4, since the contact portion 11c is located on the outer wall surface side of the body portion 10, water may be collected even if a gap is created between the body portion 10 and the contact portion 11c. Nothing happens, and durability is improved. Also,
In any of the embodiments of FIGS. 2 to 4, the contact portion 11c
The strength of the lower flange 11 is dramatically improved by coupling the to the body portion 10. The can body 1 is manufactured by joining a pair of can body halves 1a, 1a in the shape of a half-split tube by brazing in a furnace (see FIG. 1). It is desirable to bond by brazing.

By the way, as shown in FIG. 5, each of the can body half portions 1a has a lower flange 11 and an upper flange 12 bent at both side edges of a blank 1 '(copper plate) having a flat plate portion serving as a body portion 10. After that, the blank 1'is manufactured by bending it into a half-split cylinder. When bending the lower flange 11, as shown in FIG. 6, first, the side edge of the blank 1 ′ is hemmed to form the overlapping flange portion 11b, and then the hemming portion is bent to form the overlapping flange portion 11b. To form a bent flange portion 11a. Here, in the embodiment of FIG. 4, it is necessary to accurately match the hemming width and the subsequent bending width, but in the embodiments of FIGS. It can be absorbed as a width change of 11c, and processing becomes easy.

Bending of the blank 1'for manufacturing the can half portion 1a is performed by using a bending die composed of a punch 100 and a die 101 shown in FIGS. By pushing in as shown in FIGS. 8 (A) to 8 (E). Here, since the upper flange 12 is formed with the notch 12a that matches the corner portion of the can half portion 1a, the upper flange 12 does not resist bending, but the lower flange 11 has the above-mentioned shape. Since the structure is a heavy-folding structure and no notch is formed, the resistance of the lower flange 11 to bending is large, and distortion such as wrinkling of the lower flange 11 at the corner portion of the can half part 1a easily occurs. Become.

Therefore, in this embodiment, a flange retainer 101a is attached to the main body of the die 101 as shown in FIG. 7, and a groove portion for receiving the lower flange 11 is sandwiched between the die main body and the flange retainer 101a from both sides in the plate thickness direction. 101b is formed. According to this, the blank 1 ′ can be bent while the lower flange 11 is restricted by the groove portion 101b so as not to be distorted in the plate thickness direction, and the lower flange 11 is not distorted such as wrinkled. During this bending process, a strong force is applied to the outer wall surface of the body portion 10 near the lower flange 11, but in the case of FIG. 2 this portion is covered with the contact portion 11c, which also helps prevent scratches.

Further, in this embodiment, the recess depth L of the die 101 is 2.5 which is the radius of curvature R of the corner portion of the can half portion 1a.
It is set more than twice. The recess depth of the conventional die is about twice the radius of curvature R of the corner portion, and the bending process is completed in the state of FIG. The part remains open in a V shape. On the other hand, in the present embodiment, the blank 1 ′ is pushed into the die 101 up to the state of FIG. In order to reliably prevent bending defects, the die 101
It is desirable to set the recess depth L of 3 to 3 times or more of the radius of curvature R of the corner portion of the can half portion 1a. In this embodiment, the die 10 is fitted to the two corners of the can half part 1a.
Although 1 is divided into two, a single U-shaped die may of course be used.

Further, in the structure shown in FIG. 1, only the lower flange 11 has a double-folded structure, but the upper flange 12 has
It is also possible to omit the flange plate 13 by forming a double-folded structure similar to the lower flange 11. Further, it is also possible to fold two or more overlapping flanges 11b on the bending flange portion 11a to form a triple or more folded structure.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a heat exchanger including a can body of the present invention.

FIG. 2 is a sectional view of a joint flange portion of the first embodiment of the can body of the present invention.

FIG. 3 is a sectional view of a joint flange portion of a second embodiment of the can body of the present invention.

FIG. 4 is a sectional view of a joint flange portion of a third embodiment of the can body of the present invention.

FIG. 5 is a perspective view showing a blank in which a joining flange is bent.

FIG. 6 is a diagram showing a bending process of the joining flange.

FIG. 7 is a perspective view showing a bending die used for carrying out the method of the present invention.

FIG. 8A to FIG. 8E are process diagrams showing a state from an initial stage of bending of a blank by a bending die to completion thereof.

FIG. 9 is a sectional view of a joining flange portion of a conventional example.

[Explanation of symbols]

1 ... Can body 1 '... Blank 1a ... Can body half 1
0 ... Body part 11 ... Joining flange 11a ... Bending flange part 11b ... Stacking flange part 11c ... Connection part
100 ... Punch 101 ... Die 101b ... Groove

Claims (5)

[Claims] 1. A canister for a heat exchanger comprising a body portion and a joint flange bent to an edge of the body portion for joining to another casing, wherein the joint flange is a bending flange portion continuous with the body portion and a bending flange. A can body for a heat exchanger, which has a double-folded structure having an overlapping flange portion that is folded in a portion, and a contact portion for the body portion is formed in the overlapping flange portion. 2. The heat exchanger can body according to claim 1, wherein an end of the overlapping flange portion is bent along the body portion to form the contact portion. 3. The heat exchanger according to claim 1, wherein the overlapping flange portion is folded on the surface of the bending flange portion on the body portion side, and the contact portion is brought into contact with the outer wall surface of the body portion. Can body. 4. The heat exchanger can body according to claim 1, wherein the contact portion is connected to a body portion. 5. A method for manufacturing the can body for a heat exchanger according to claim 1 by joining a pair of can body halves in a half-split tube shape, each can body comprising: When manufacturing the half part, after bending the joining flange on the side edge of the blank having the flat plate part to be the body part, using a bending die composed of a punch and a die, the blank is pushed into the die by the punch and the half-split cylinder In the case of bending into a shape, the heat exchange is characterized in that a groove is formed in the die so as to sandwich the joint flange from both sides in the plate thickness direction, and the bending is performed in a state in which the distortion of the joint flange is restricted by the groove. A method for manufacturing a container body.