JPH07324883A - Manufacture of heat exchanger - Google Patents

Abstract

PURPOSE:To improve a heat exchanging performance and reliability in operation by a method wherein a recessed part is prevented from being deformed while a pipe is being expanded with a U-pipe being inserted into fins having a notch and a bending angle of each of the fins is assured. CONSTITUTION:In a heat exchanger in which a plurality of fins 6 formed with notches 9 are piled up from each other and the fins are bent and folded in such a way that spacings at the notch may be narrowed, the notches are formed such that they have parallel sides 9c, 9c substantially in perpendicular to a side of a longitudinal direction of each of the fins. Then, a U-pipe inserting step and a pipe diameter expanding step are carried out by inserting an inserting and fitting part 16 of a jig 15 for use in preventing deformation into each of the notches of the fins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger used in, for example, an air conditioner, and more particularly to an improvement in a method of manufacturing a multi-stage folding type heat exchanger.

[0002]

2. Description of the Related Art A commonly used air conditioner comprises an indoor unit arranged in an air-conditioned room and an outdoor unit arranged outdoors, and these units are connected by a refrigerant pipe and electric wiring. .

From the user side, there is a great demand for miniaturization of these units and reduction of the installation space, and each manufacturer must increase the heat exchange capacity while satisfying such conditions.

Various improvements have been made especially in the indoor unit. One of them is the adoption of a multi-stage bending type heat exchanger. In this method, a plurality of cutouts are provided at predetermined intervals on the fins forming the heat exchanger, a plurality of fins are stacked, and then the cutouts are bent.

That is, in the state where the heat exchanger is bent in multiple stages and arranged in a unit body having suction ports on the front surface and the upper surface, a large front surface area can be secured, while the heat exchange efficiency is improved. There is an advantage that the size of the unit body can be suppressed and the miniaturization can be promoted.

[0006]

By the way, in manufacturing such a heat exchanger, fins are stacked with a narrow gap therebetween and then formed into a U-shape in a pipe insertion hole provided in the fin. The U pipe which is the heat exchange pipe is inserted.

Then, the U pipe inserted into the fin is expanded in the radial direction so as to be securely attached and fixed to the fin. Further, the notch of the fin is bent, and the open ends of the U pipes adjacent to each other before and after the bending are connected by a return bend.

Particularly, in the step of expanding the U pipe, a mandrel is inserted into the U pipe. At this time, the long side portions on both sides of the stacked fins are held by a jig so as to prevent the U pipe from bending and to expand the pipe uniformly in the radial direction.

However, the fin is provided with the notch as described above, and particularly when the U pipe inserted into the pipe insertion holes on both sides of the notch is expanded, the expansion deformation force of the U pipe is cut. There is a risk that it may be transmitted to the notch and partially expanded and deformed.

For the U pipe, bending occurs, and it becomes impossible to obtain a predetermined bending angle with the fins bent. Eventually, heat exchange performance will vary, leading to reduced reliability.

Further, after the U pipe is expanded, the fins are bent, but the return bend which is not in a position straddling the notch is connected before the fin is bent, and the return bend in a position straddling the notch is bent after the fin is bent. Connecting.

That is, since the U pipe has both open ends free and its strength is weak as it is, the return bend is connected as much as possible to secure the strength when the fin is bent.

The return bend to be connected before bending the fins is selected so as not to straddle the notch.
This is because the U-pipe connection end spacing of the return bend does not change even when the fin is bent.

The return bend, which is connected after the fin is bent, is located at a position straddling the notch. This is because the distance between U-pipe open ends located on both sides of the notch is narrowed by bending the fins, and connecting a return bend that straddles the notch according to that dimension will not cause an error. is there. .

Thus, although there is no dimensional error in the return bend connecting step, this connecting step needs to be performed twice before and after the fin bending step, which is an extremely troublesome work and the workability is poor. .

If all the return bend connecting processes are completed before the fin bending process, it is convenient to maintain the strength of the fins and the U pipe and improve workability.
The return bend used conventionally is a U-shaped tube itself, and the length of the parallel straight portions forming both open ends is extremely short, and the return bend is bent with a minimum radius of curvature so as to save space.

If such a return bend is directly connected to a position extending over both sides of the cutout portion and the fins are bent, the space between the return bend and the U pipe is narrowed, which is large. Reduction stress is applied.

The occurrence of this contraction stress may lead to deformation of the connection portion between the return bend and the U pipe and refrigerant leakage due to cracks in the return bend itself. Therefore, it is necessary to take some kind of stress absorbing measure in the return bend connected to the position across the notch.

The present invention has been made in view of the above circumstances. A first object of the present invention is to deform the cutout portion in a state where the U pipe is inserted into the fin having the cutout portion and expanded. To secure the bending angle of the fin,
An object of the present invention is to provide a method for manufacturing a heat exchanger with improved heat exchange performance and reliability.

The second object is to connect all the return bends to the U pipes before bending the laminated fins so that the strength can be maintained and the workability can be improved and the cutouts can be straddled. Manufacture of a heat exchanger that efficiently absorbs and reduces the reduction stress of the return bend and prevents deformation of the connection part between the return bend and the U pipe and the return bend itself to improve heat exchange performance and reliability. It is intended to provide a method.

[0021]

In order to satisfy the first object, a method of manufacturing a heat exchanger according to a first aspect of the present invention is the method of manufacturing a heat exchanger according to claim 1, wherein the fin and the heat exchange pipe bent in a U shape are used. A fin stacking step of stacking a plurality of fins each having a U pipe and a return bend that is a U-shaped pipe and having a hole for inserting the pipe and a notch formed therein, and inserting the U pipe into the stacked fins. In a method of manufacturing a heat exchanger, which comprises a U pipe inserting step, a pipe expanding step of expanding the inserted U pipe, and a bending step of bending the fins so that a cutout space of the stacked fins is narrowed, The pipe inserting process and the pipe expanding process are characterized in that a jig for preventing deformation is inserted into the notch portion of the fin.

According to a second aspect of the present invention, the notch provided in the fin according to the first aspect has a pair of side portions that are substantially perpendicular to the sides of the fin in the longitudinal direction and are parallel to each other. The jig for preventing deformation, which is formed, includes an insertion fitting portion that is inserted between the parallel side portions of the cutout portion.

In order to satisfy the second object, the heat exchanger manufacturing method of the second invention is the method of manufacturing a heat exchanger according to claim 3,
U pipe, which is a heat exchange pipe bent in a U shape, and U
A fin stacking step of stacking a plurality of fins, each of which is formed of a return bend, which is a character tube, and having a hole for inserting a pipe and a notch formed therein, and a U pipe inserting step of inserting the U pipe into the stacked fins. , This inserted U
A pipe expanding step, a return bend connecting step of connecting the expanded ends of the expanded U pipe to each other by the return bend, and a bending step of bending the fins so that the cutout space of the laminated fins is narrowed. In the method of manufacturing the heat exchanger, the U located on both sides of the cutout portion in the return bend connection step.
The return bend connected between the pipes and straddling the cutout portion is characterized in that the leg portion is formed in a long straight shape, and in the bending step, the return bend is connected and bent.

In order to satisfy the same object, a method for manufacturing a heat exchanger according to a third aspect of the present invention is the method of manufacturing a heat exchanger according to claim 4, wherein the fin, the U pipe which is a heat exchange pipe bent in a U-shape, and the U-shaped pipe. And a U pipe inserting step of inserting the U pipe into the laminated fins, and a fin laminating step of stacking a plurality of the fins each having a notch portion and a hole for inserting the pipe. A pipe expanding step of expanding the inserted U pipe, a return bend connecting step of connecting the open ends of the expanded U pipe with each other by the return bend, and a fin so that a cutout space of the laminated fin is narrowed. In the method of manufacturing the heat exchanger, which comprises a bending step of bending the U pipe, the U pipes located on both sides of the cutout portion are connected and cut in the return bend connecting step. The return bend across the off portion together with those having flexibility is used, in the folding process, characterized in that it is bent while connecting the return bend.

[0025]

In the first aspect of the invention, the fin notch is provided with a pair of side portions that are perpendicular to the longitudinal side and are parallel to each other.
The insertion part of the jig is engaged with this to prevent the bulging deformation of the side edge of the notch when inserting the U pipe and expanding the pipe.

In the second and third inventions, the return bend extending over the notch portion of the fin has a straight leg shape with long legs or is flexible, and is generated when the fin is bent. Absorb and reduce shrinkage stress.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, to which a heat exchanger provided in an indoor unit of an air conditioner is applied. As shown in FIG. 1, a front suction port 2a is opened on the front side of a unit body 1 which is an air conditioner body, and a grill 3a is fitted therein. On the other hand, the upper suction port 2b is opened on the upper surface side and the grill 3b is fitted therein.

An outlet 4 is provided from the front surface of the unit body 1 to the lower portion. An air filter (not shown) and a molded heat exchanger 5 (described later) are arranged so as to face the front part, which is the upper part of the outlet 4, and the upper intakes 2a and 2b.

FIG. 2 (B) shows the fins 6 forming the heat exchanger 5. This is formed in a straight shape having a short width in the left-right direction and a long length in the up-down direction in the drawing. A V-shaped notch 7 that is horizontal from one side edge 6a and extends from the middle of the side edge 6a is provided at a predetermined position on the upper side and extends slightly to the front side of the other side edge 6b.

As will be described later, the fin 6 is bent, but in this bent state, the cut portion 7 is formed.
The portion between the tip of the and the fin side edge 6b is left as the first connecting portion 8.

A plurality of cutouts 9 are provided at a predetermined interval from the cutout 7 to the lower edge of the fin 6. As shown in FIG. 3A, the cutout portion 9 is composed of an upper side portion 9a and a lower side portion 9b, and each side portion bends at least a plurality of straight lines in different directions in a zigzag shape,
It is formed in a bent and deformed triangular shape as a whole.

However, the notched open ends of the upper side portion 9a and the lower side portion 9b are parallel side portions 9c, 9c in a direction substantially orthogonal to the fin side end edge 6b. In other words, the notch 9 has a side portion that is substantially perpendicular to the side of the fin 6 in the longitudinal direction.

The tip 9d of the notch 9 has a fin side edge 6a.
It is extended to the near side of the
A portion between d and the fin side edge 6a is left as a second connecting portion 10 when the fin 6 is bent.

A joint portion 11 is integrally provided between the parallel side portion 9c, which is a midway portion between the upper and lower side portions 9a and 9b, and the tip 9d, and is installed between the upper and lower side portions. A substantially middle portion of the connecting portion 11 is formed in advance in a triangular shape in cross section so as to project in a predetermined plane direction, and folds are provided at the top portion and the base end portion.

As shown in FIG. 3B again, the fin 6 is provided with a plurality of pipe insertion holes 12 which are arranged in two rows on the left and right and which are vertically spaced from each other by a predetermined distance.
A rising slit is formed between the insertion holes 12 except the insertion holes 12 on the upper and lower sides via the cutout portion 7 and between the insertion holes 12 on the upper and lower sides via the cutout portion 9. .. are provided.

The rising slits 13 are formed by the fins 6
It is composed of rising pieces that are integrally cut and raised on both sides of the fins in the vertical direction (step direction), and can efficiently contact heat exchange air guided along both sides of the fin during heat exchange action. .

In manufacturing the heat exchanger 5, a fin laminating step is first performed in which a plurality of fins 6 thus constructed are stacked with a predetermined jig at a predetermined narrow interval.

At this time, it goes without saying that the positions of the notches 7 and the notches 9 provided on the fin 6 are accurately aligned with each other, and the positions of the pipe insertion holes 12 are exactly opposite to each other.

After laminating a predetermined number of fins 6, as shown in the figure, jigs 15 for preventing the deformation of the notch 9 must be set on the both side edges 6a, 6b. The jig 15 is composed of a first jig 15a and a second jig 15b.

The first jig 15a has a full length which abuts on the fin side edge 6b facing the open end of the notch 9 and over the entire length thereof. A plurality of insertion portions 16 ... Protruding on the fin side edge 6b side are integrally provided.

The insertion portion 16 projects perpendicularly to the longitudinal direction of the jig 15a, and its pitch is the same as the pitch of the cutout portion 9. The protruding length is almost the same as that of the longer parallel side portion 9c, and the thickness thereof is the parallel side portion 9c.
It is almost the same as the c and 9c spacing.

By bringing the first jig 15a into close contact with the fin side edge 6b, the insertion portions 16 ... Are inserted into the notches 9. That is, the insertion portion 16 is inserted into the parallel side portions 9c, 9c forming the cutout portion 9 and comes into close contact with each other.

The second jig 15b has a fin side edge 6a.
In addition, it has a full length in which it abuts in the entire longitudinal direction, and is a straight shape without any protrusion. The fin 6 is sandwiched from both sides by the first jig 15a and the second jig 15b.

As shown in FIG. 3, end plates 17 having a relatively large thickness are provided at both ends of the fins 6 to be laminated, and the fins 6 are held by the jig 15 not shown here.
Then, a pipe inserting step of inserting a U pipe 18, which is a heat exchange pipe bent in a U shape, into the pipe inserting hole 12 provided in the end plate 17 is performed.

The insertion position of the U pipe 18 with respect to the fin 6 is, as shown in FIG. 2B again, all the positions which are in an oblique posture across the pipe insertion holes 12, 12 in the left and right rows.

Again, as shown in FIG. 3, the inserted U
The U-shaped bent portion 18a of the pipe 18 projects from the one end plate 17, while the open end 18b, which is the other end, of the other end plate 17.
Stick out from.

With this state maintained, the process of expanding the U pipe 18 is started. That is, the mandrel is inserted from the opening end of the U pipe 18 and bulged and deformed in the radial direction. The U pipe 18 is securely fitted and fixed to the fin 6.

During the inserting process of the U pipe 18 into the fin inserting hole 12 and the expanding process of the U pipe, the inserting portions 16 of the jig 15a are inserted into all the notches 9. ing.

The fin 6 itself has an extremely thin plate thickness and is easily deformed. When the U pipe 18 is inserted into the fin 6 as described above, even if the insertion direction is slightly deviated, the deformation biasing force acts on the fin. Furthermore, if the inserted U pipe 18 is expanded, the deformation biasing force on the fins cannot be ignored.

In particular, the insertion holes 12 and 1 on both sides of the notch 9
The U pipe 18 inserted and expanded in 2 tries to affect the deformation of the notch. However, since the insertion portion 16 of the first jig 15a is inserted into the parallel side portions 9c, 9c formed in the cutout portion 9, this insertion portion ensures the deformation of the cutout portion. Block.

Further, since the notch 9 is not deformed, the U pipe 18 to be inserted is not bent, and an accurate straight shape is maintained. Then, as will be described later, the set bending angle can be reliably obtained in a state where the laminated fins 6 are bent.

When the expanding process of the U pipes 18 is completed, the process goes to a return bend connecting process in which the open ends of the adjacent U pipes 18 are connected by the return bend 19 made of a U-shaped pipe.

Actually, in FIG. 2B, the uppermost portion U
The left open ends of the pipes 18, the right open ends of the lowermost U pipes 18, and the open ends of the U pipes 18, 18 that are vertically adjacent to each other in the left and right rows are returned, leaving the position across the notch 9. Connect at bend 19. The U pipe 18 and the return bend 19 form a series of meandering flow paths.

Then, the step of bending the notch 7 and the notch 9 is started. First, the notch 7 is bent. At this time, a biasing force is applied from one side edge 6a of the fin 6 to the other side edge 6b. By making a bend at a set angle, the heat is divided into two parts in an inverted V shape, which is bent again at the upper part and the lower part side from the cut portion 7 as shown in FIG. It becomes the exchanger 5.

Here, since the heat exchanger portion on the upper side of the cut portion 7 is bent and formed on the rear surface side of the unit main body 1, it is referred to as the rear surface side heat exchanger 5B, and the heat on the lower side of the cut portion 7 is called. From the portion where the exchanger portion is bent and formed on the front side of the unit body 1, the front side heat exchanger 5
Call A.

The front side heat exchanger 5A is further bent along a plurality of notches 9 ... The notch 9 of the manufactured fin 6 has a shape in which the upper and lower sides 9a and 9b are separated from each other, but the upper and lower sides are almost in close contact with each other in a bent state.

After this, the bent notch 9 is formed.
Connect the return bend at the position that straddles. A cross-flow fan F, which constitutes an indoor blower, is arranged at the back side portion of the front side heat exchanger 5A. The cross-flow fan F is covered by an inverted V-shaped bent portion of the front side heat exchanger 5A and the rear side heat exchanger 5B as if it were an umbrella shape.

Since the indoor unit of the air conditioner has such a structure, the heat exchanger 5 acts as an evaporator when the cooling operation is performed, and the heat exchanger 5 acts as a condenser when the heating operation is performed. To do.

As a second embodiment, as shown in FIG.
The return bends 20 and 30 to be described later, which are connected to the cutout portions 9 of the fins 6 that form the heat exchanger 5 and which are hatched in the drawing, are provided at positions that do not cross the other cutout portions 9. It is distinguished from the return bend 19 that is given.

That is, as shown in FIG. 2 (B), the U pipe 18 is inserted into the fin 6 at all diagonal positions across the pipe insertion holes 12 in the left and right rows. .

The return bends 19 connected to the adjacent U pipes 18 are arranged in the vertical direction of the left and right rows, leaving one open end of the uppermost U pipe 18 and one open end of the lowermost U pipe 18. The open ends of the adjacent U pipes 18, 18 are provided to each other.

From such position setting, it is divided into either the return bends 20 and 30 which straddle the notch 9 or the return bend 19 which does not straddle the notch. Figure 5
As shown in (A), the return bend 20 provided at the position straddling the notch 9 has a straight shape in which the legs 20a, 20a are long. The return bend 19 used at a position that does not straddle the notch 9 is shown by a chain double-dashed line in the figure, but it can be seen that the leg 19a is extremely short. The radii of curvature of the bent portions 20b and 19b may be the same.

As shown in FIG. 6B, the distance A from the end plate 17 of the fins 6 to be stacked to the tip of the bent portion 20b of the return bend 20 connected to the position across the notch 9.
Has a length that is at least about 1.5 times the distance B to the tip of the bent portion 19b of the return bend 19 that does not straddle the notch 9.

As shown in FIG. 9A again, the notch 9
The return bend 20 connected to the position crossing over the legs 6 has its legs 20a, 20a parallel to each other before the fins 6 are bent, but as shown in FIG. The distance between the base ends is narrowed.

However, the bent portion 20b of the return bend 20 has almost no change in radius of curvature because the legs 20a and 20a are long. Legs 20a, 20
It is unavoidable that a certain degree of inclination is generated from the base end portion of a to the curved portion 20b, but the angle θ is extremely small, and therefore, reduction stress is hardly generated.

Further, there is no inclination in the connecting portion with the U pipe 18 which is the base end portion of the return bend 20, and therefore there is no room for deformation accidents in these mutual connecting portions.

A return bend 30 extending over the notch 9 as shown in FIG. 6 (A) is also sufficient. This is a leg 30a which is straight from the base end and parallel to each other,
30a is provided, and the bent portion 30b bulges from the leg portion.

The central portion of the bent portion 30b is formed in a straight shape, and the presence of the bent portion 30a and the straight portion 31 allows the return bend 30 to have some flexibility.

Then, when the return bend 30 is connected to a position straddling the notch 9 and compared with other return bends 19, the bend of the return bend 30 connected to the position straddling the notch 9 from the end plate 17 is bent. Distance C to Narube 30b
Is longer than the other distance B to the bent portion 19b of the return bend 19.

When such a return bend 30 is connected at a position straddling the notch 9 and the fin 6 is bent, the distance between the base ends of the legs 30a, 30a in the bent state is narrowed, but the bent portion 30b is bent. The straight portion 31 provided absorbs the deformation of the entire bend.

Therefore, there is almost no reduction stress generated in the return bend 30, and there is no inclination at the connecting portion with the U pipe 18 which is the base end portion of the return bend 30. No accidents occur.

Further, as shown in FIG. 6 (B), the bending portion 3
If the central portion of 0b is formed in a bellows shape and the bellows portion 32 makes the return bend 30 more flexible, the reduction stress can be more absorbed.

[0073]

As described above, according to the first aspect of the present invention, there is provided the heat exchanger in which the fins are bent so that the space of the cutout portions of the fins is narrowed. Since a vertical side portion is provided, a jig is engaged with the side portion, and then the U pipe is inserted and expanded,
Prevents bulging deformation of the notch due to insertion and expansion of the pipe, eliminates bending of the U pipe, and makes it possible to accurately determine the bending angle of the fins, improving heat exchange performance and reliability. It has the effect of being cut.

According to the second and third aspects of the present invention, there is provided the heat exchanger in which the fins are bent so that the space of the cutout portions of the fins is narrowed, and the return bend that straddles the cutout portions is
Since the contraction stress due to the bending of the fins is absorbed, the deformation of the connection portion between the return bend and the U pipe and the return bend itself is prevented, and the heat exchange performance and the reliability are improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an air conditioner indoor unit including a heat exchanger, showing an embodiment of the present invention.

FIG. 2A is an enlarged view showing a part of a fin and a jig for preventing deformation of the embodiment. FIG. 6B is a front view of the entire fin and a part of the deformation preventing jig.

FIG. 3 is an explanatory view of connecting a return bend to a fin and a U pipe inserted in the fin in the embodiment.

FIG. 4 is a side view of the molded heat exchanger according to the embodiment.

FIG. 5A is a front view of a return bend of another embodiment. (B) is a front view of a part of the molded heat exchanger.

FIG. 6A is a front view of a part of a molded heat exchanger according to still another embodiment. (B) is a front view of the return bend.

[Explanation of symbols]

6 ... Fins, 9 ... Notch, 5 ... Heat exchanger, 18 ... U pipe, 19, 20, 30 ... Return bend, 20a ...
Legs (of return bend), 31 ... Bellows (of return bend).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Kurata 336 Tatehara, Fuji City, Shizuoka Prefecture Toshiba Corporation Fuji Factory

Claims (4)

[Claims] 1. A fin comprising a fin, a U pipe that is a U-shaped bent heat exchange pipe, and a return bend that is a U-shaped pipe, and a cutout portion is formed together with a hole for inserting the pipe. A step of stacking a plurality of fins, a step of inserting the U-pipe into the stacked fins, a step of expanding the inserted U-pipe, and a cutout space of the stacked fins In the method of manufacturing a heat exchanger, which comprises a bending step of bending the fins so that the fins are narrowed, the U pipe inserting step and the pipe expanding step are performed by inserting a deformation preventing jig into the notch portion of the fin. And a method for manufacturing a heat exchanger. 2. The notch provided in the fin,
The deformation preventing jig is formed so as to have a pair of side portions that are substantially perpendicular to the longitudinal side of the fin and are parallel to each other. The deformation preventing jig is inserted between the parallel side portions of the cutout portion. The heat exchanger manufacturing method according to claim 1, further comprising: 3. A fin comprising a fin, a U pipe which is a U-shaped bent heat exchange pipe, and a return bend which is a U-shaped pipe, and a notch formed together with a hole for inserting the pipe. A step of stacking a plurality of fins, a step of inserting the U pipe into the stacked fins, a step of expanding the inserted U pipe, and an opening end of the expanded U pipe to each other. In a method for manufacturing a heat exchanger, which comprises a return bend connecting step of connecting the above with a return bend, and a bending step of bending the fins so that the cutout spaces of the stacked fins are narrowed, in the return bend connecting step, The return bend connected between the U pipes located on both sides of the cutout portion and straddling the cutout portion is formed in a straight shape with long legs. Both in the above-described folding process, the manufacturing method of the heat exchanger, characterized in that bent while connecting the return bend. 4. A fin comprising a fin, a U pipe that is a U-shaped bent heat exchange pipe, and a return bend that is a U-shaped pipe, and a cutout portion is formed together with a hole for inserting the pipe. A step of stacking a plurality of fins, a step of inserting the U pipe into the stacked fins, a step of expanding the inserted U pipe, and an opening end of the expanded U pipe to each other. In a method for manufacturing a heat exchanger, which comprises a return bend connecting step of connecting the above with a return bend, and a bending step of bending the fins so that the cutout spaces of the stacked fins are narrowed, in the return bend connecting step, A flexible return bend is used for connecting the U pipes located on both sides of the cutout and straddling the cutout. Serial in folding process, the manufacturing method of the heat exchanger, characterized in that bent while connecting the return bend.