JP3312990B2 - Heat exchanger manufacturing method - Google Patents

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 for manufacturing a multi-fold type heat exchanger.

[0002]

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

[0003] From the user's side, there is a great demand for miniaturization of these units and a reduction in installation space, and each manufacturer must try to increase the heat exchange capacity while satisfying such conditions.

Various improvements have been made particularly to indoor units. One of them is the adoption of a multi-stage folding type heat exchanger. In this method, a plurality of notches are provided at predetermined intervals in fins constituting a heat exchanger, and a plurality of fins are stacked, and then the notches are bent.

[0005] That is, a heat exchanger which is bent in multiple stages is provided in a unit body having a suction port on the front surface or the upper surface, and a large front surface area is ensured, while the heat exchange efficiency is improved. There is an advantage that the size of the unit body can be reduced and the size of the unit body can be reduced to promote the miniaturization.

[0006]

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

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

In particular, the step of expanding the U pipe is performed by inserting a mandrel into the U pipe. At this time, the long sides of both sides of the stacked fins are held by jigs so as to prevent the U-pipe from bending and uniformly expand in the radial direction.

However, the fin is provided with the notch as described above. In particular, when the U pipe inserted into the pipe insertion holes on both sides of the notch is expanded, the expanded deformation force of the U pipe is cut off. There is a possibility that the light is transmitted to the notch and partially swells and deforms.

[0010] For the U pipe, bending occurs, and a predetermined bending angle cannot be obtained in a state where the fin is bent. Ultimately, the heat exchange performance varies, leading to a reduction in reliability.

After the U pipe is expanded, the fins are bent. A return bend not located at a position straddling the notch is connected before bending the fin. A return bend at a position straddling the notch is bent after the fin is bent. Connecting.

That is, since the open ends of the U pipe are free and the strength is weak as it is, the return bend is connected as much as possible to secure the strength at the time of bending the fin.

As the return bend to be connected before the fin is bent, a return bend that does not straddle the notch is selected.
This is because the interval between the U-pipe connection ends of the return bend does not change at all even if the fin is bent.

The return bend connected after bending the fin is located at a position straddling the notch. This is because the interval between the open ends of the U-pipe located on both sides of the notch is narrowed by bending the fin, and no error occurs if a return bend that spans the notch is connected to that size. is there. .

As described above, although there is no dimensional error in the connection step of the return bend, this connection step needs to be performed twice before and after the fin bending step, which is extremely troublesome work and poor workability. .

Completing the connection step of all the return bends before the fin bending step can advantageously maintain the strength of the fin and the U pipe and improve the workability.
The return bend conventionally used is a U-shaped tube itself, and the length of the parallel straight portions constituting both open ends is extremely short, and is bent with a minimum radius of curvature so as to take up no space.

If such a return bend is connected to a position straddling both sides of the notch as it is and the fin is bent, the interval between the connection portions between the return bend and the U pipe is reduced, and the return bend becomes larger. Reduced stress will be applied.

The generation of the reduced stress may cause a deformation of a connection portion between the return bend and the U pipe and a refrigerant leak due to a crack in the return bend itself. Therefore, it is necessary to take some stress absorbing measures in the return bend connected to the position straddling the notch.

[0019] The present invention has been made in view of the above circumstances, and has as its object to prevent deformation of the cutout portions in a state where the fin having a notch was inserted by tube expansion of the U pipe Another object of the present invention is to provide a method of manufacturing a heat exchanger in which the fins are bent at a desired angle to improve heat exchange performance and reliability.

[0020] Incidentally, all the return bend before bending the laminated fins connected to the U pipe, resulting an improvement in workability strive to retain the strength, and astride the return bend of the reduced stress in the notch Is efficiently absorbed and reduced to prevent deformation of the connection between the return bend and the U pipe and the return bend itself, thereby improving the heat exchange performance and reliability .

[0021]

[Means for Solving the Problems] In order to satisfy the above-mentioned purpose
The method for manufacturing a heat exchanger according to the present invention , in claim 1, comprises a fin, a U pipe that is a heat exchange pipe bent in a U shape, and a return bend that is a U-shaped pipe. A fin stacking step of stacking a plurality of the fins each having the notch formed with the hole, a U pipe insertion step of inserting the U pipe into the stacked fins, and an expanding step of expanding the inserted U pipe; A method for manufacturing a heat exchanger, comprising: a bending step of bending the fins such that the cutout space of the stacked fins is reduced.
The U-pipe insertion step and the pipe expansion step are performed by inserting a jig for preventing deformation into the notch of the fin.

Further, in the second aspect, the notch provided in the fin according to the first aspect has a pair of sides substantially perpendicular to a longitudinal side of the fin and parallel to each other. The jig for preventing deformation is provided with an insertion portion that is inserted between the parallel sides of the cutout portion.

[0023]

[0024]

[0025]

In the present invention , a pair of sides perpendicular to the longitudinal side and parallel to each other are provided in the notch of the fin. This prevents bulging deformation of the notch side edge during pipe expansion.

[0026] Incidentally, straddle return bends in the notch of the fins, by employing a material having those legs long straight or flexible, absorbing the reduced stresses generated during the bending of the fins Can be reduced.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings, in 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 main body 1, which is an air conditioner main body, and a grill 3a is fitted therein. On the other hand, the upper suction port 2b is also opened on the upper surface side, and the grill 3b is fitted.

An outlet 4 is provided from the front to the lower part of the unit body 1. An air filter (not shown) and a molded heat exchanger 5, which will be described later, are arranged opposite the front part, which is the upper part of the outlet 4, and the upper inlets 2a, 2b.

FIG. 2B shows the fins 6 constituting the heat exchanger 5. This is formed in a straight shape with a short width in the left-right direction and a long length in the vertical direction in the figure. At an upper predetermined position, a V-shaped cut portion 7 is provided horizontally from one side edge 6a, and a V-shaped cut portion is provided from a halfway portion, and extends slightly to the near side of the other side edge 6b.

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

A plurality of notches 9 are provided at predetermined intervals from the notch 7 to the lower edge of the fin 6. The notch 9 includes an upper side 9a and a lower side 9b as shown in FIG. 9A, and each side is formed by zigzag bending at least a plurality of straight lines in different directions.
As a whole, it is formed in a bent and deformed triangular shape.

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 edge 6b. In other words, the notch 9 has a side substantially perpendicular to the side of the fin 6 in the longitudinal direction.

The front end 9d of the notch 9 has a fin side edge 6a.
Of the notch 9
The space between d and the fin side edge 6a is left as the second connecting portion 10 when the fin 6 is bent.

A connecting portion 11 is provided integrally between the parallel side portion 9c, which is a middle portion between the upper and lower sides 9a and 9b, and the tip 9d, and is bridged between the upper and lower sides. A substantially intermediate portion of the connecting portion 11 is formed in a triangular cross section so as to protrude in a predetermined plane direction in advance, and has a fold at a top portion and a base end portion.

As shown in FIG. 3B again, the fin 6 is provided with a plurality of pipe insertion holes 12 arranged in two rows on the left and right sides and at predetermined intervals in the vertical direction.
A rising slit is formed between 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 notch 9. The parts 13 are provided.

These rising slit portions 13 are provided with fins 6.
Of the fins are formed in the vertical direction (the stepwise direction) of the fin and integrally formed on both surfaces thereof, and can efficiently contact the heat exchange air guided along both surfaces of the fins during the heat exchange operation. .

In manufacturing the heat exchanger 5, the fin laminating step of stacking a plurality of the fins 6 configured as described above using a dedicated jig at a predetermined small interval is first.

At this time, it goes without saying that the positions of the cut portions 7 and the cutout portions 9 provided on the fins 6 are precisely aligned with each other, and the positions of the pipe insertion holes 12 are accurately opposed with each other.

After a predetermined number of fins 6 have been stacked, a jig 15 for preventing deformation of the notch 9 must be set on both side edges 6a and 6b as shown in FIG. The jig 15 includes a first jig 15a and a second jig 15b.

The first jig 15a has a total length in contact with the fin-side edge 6b facing the open end of the notch 9 and along the entire length thereof. A plurality of insertion portions 16 projecting toward the fin side edge 6b 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 notch 9. The protruding length is almost the same as that of the longer parallel side portion 9c, and its thickness is the parallel side portion 9c.
It is almost the same as the c and 9c interval dimensions.

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

The second jig 15b has a fin side edge 6a.
It has a full length that abuts over the entire longitudinal direction, and is straight without any protrusions. The fin 6 is clamped from both sides by the first jig 15a and the second jig 15b.

As shown in FIG. 3, end plates 17, 17 having a relatively large thickness are provided on both side ends of the fins 6 to be laminated, and are held by the jig 15 (not shown).
Then, the process proceeds to a pipe insertion step of inserting a U pipe 18 which is a U-shaped heat exchange pipe into the pipe insertion hole 12 provided in the end plate 17.

As shown in FIG. 2B, the insertion positions of the U pipe 18 into the fins 6 are all positions where the U pipe 18 is in an oblique attitude across the pipe insertion holes 12 in the left and right rows.

As shown in FIG. 3 again, the inserted U
The U-shaped bent portion 18a of the pipe 18 protrudes from one end plate 17 while the other open end 18b is
Protruding from.

While maintaining this state, the process proceeds to the step of expanding the U pipe 18. That is, the mandrel is inserted from the open end of the U pipe 18 and swells and deforms in the radial direction. The U pipe 18 is securely fitted and fixed to the fin 6.

In the step of inserting the U-pipe 18 into the fin insertion hole 12 and the step of expanding the U-pipe, the notches 9 are fitted with the insertion portions 16 of the jigs 15a. ing.

The fin 6 itself is extremely thin and easily deformed. When the U pipe 18 is inserted into such a fin 6, even a slight shift in the insertion direction can be a deformation urging force on the fin. Furthermore, if the inserted U pipe 18 is expanded, the deformation urging force on the fin cannot be ignored.

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

Further, since there is no deformation of the notch 9, the inserted U-pipe 18 does not bend, so that an accurate straightness is maintained. Then, in a state where the stacked fins 6 are bent as described later, the set bending angle can be reliably obtained.

When the step of expanding the U pipe 18 is completed, the process proceeds to a return bend connection step of connecting the open ends of the adjacent U pipes 18 with a return bend 19 formed of a U-shaped pipe.

Actually, in FIG.
Returning the left open end of the pipe 18, the right open end of the lowermost U pipe 18, and the position straddling the notch 9, return the open ends of the U pipes 18, 18 vertically adjacent to each other in the left and right rows. Connect at bend 19. The U pipe 18 and the return bend 19 form a series of meandering flow paths.

Next, the process proceeds to a bending step for the notch 7 and the notch 9. First, the notch 7 is bent. At this time, an urging force is applied from one side edge 6a of the fin 6 to the other side edge 6b. By making a bend at the set angle, as shown in FIG. 1 again, the heat split into two parts in an inverted V-shape which is bent from the cut portion 7 into an upper portion and a lower portion side. 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 body 1, it is called a rear heat exchanger 5B, and the heat exchanger on the lower side of the cut portion 7 is formed. The heat exchanger 5 is bent from the front side of the unit body 1 to the front heat exchanger 5.
Called A.

The front-side heat exchanger 5A is further bent along a plurality of notches 9. The cutout 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 in a bent state.

After that, the bent notch 9
Connect the return bend at the position that straddles. Note that a cross-flow fan F that constitutes an indoor blower is disposed on the rear side of the front-side heat exchanger 5A. The cross flow fan F is covered like an umbrella by the inverted V-shaped bent portion of the front heat exchanger 5A and the rear heat exchanger 5B.

Since the indoor unit of the air conditioner has such a configuration, for example, when performing the cooling operation, the heat exchanger 5 functions as an evaporator, and when performing the heating operation, the heat exchanger 5 functions as a condenser. I do.

As a second embodiment, as shown in FIG.
The return bends 20 and 30 which are connected to positions where the fins 6 constituting the heat exchanger 5 straddle the notch portions 9 and which are hatched in the drawing and which will be described later are provided at positions where the other notch portions 9 do not straddle. Return bend 19 to be performed.

That is, as shown in FIG. 2B, the insertion positions of the U-pipe 18 into the fins 6 are all positions in an oblique posture over the pipe insertion holes 12 in the left and right rows. .

The return bends 19 connected to the adjacent U pipes 18 are arranged vertically in 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 are provided to each other.

From such a position setting, the return bends 20 and 30 straddling the notch 9 and the return bend 19 not straddling the notch 9 can be classified. FIG.
As shown in (A), a straight bend having long legs 20a, 20a is used as a return bend 20 provided at a position straddling the notch 9. The return bend 19 used in a position where it does not straddle the notch 9 is shown by a two-dot chain line in the figure, and it can be seen that the leg 19a is extremely short. The radii of curvature of the curved portions 20b and 19b may be the same.

As shown in FIG. 9B, 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 a position straddling the notch 9 is shown.
Has a length at least about 1.5 times the distance B to the tip of the bent portion 19b of the return bend 19 at a position not straddling the notch 9.

As shown in FIG. 9A again, the notch 9
Although the legs 20a, 20a of the return bend 20 connected to the position straddling the fins 6 are parallel to each other before the fin 6 is bent, the legs 20a, 20a are bent as shown in FIG. The distance between the proximal ends is reduced.

However, the radius of curvature of the bent portion 20b of the return bend 20 hardly changes due to the long leg portions 20a. Legs 20a, 20
Although it is inevitable that a certain degree of inclination is generated from the base end portion a to the bent portion 20b, the angle θ is extremely small, and therefore, almost no contraction stress is generated.

Further, there is no inclination at the connection with the U pipe 18 which is the base end of the return bend 20, so that there is no room for a deformation accident at these mutual connection.

A return bend 30 straddling the notch 9 as shown in FIG. This is because the legs 30a, which are straight from the base end and parallel to each other,
A bent portion 30b protrudes from the leg portion.

The center of the bent portion 30b is formed in a straight shape, and the return bend 30 has a certain degree of flexibility due to the presence of the bent portion 30a and the straight portion 31.

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

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

Therefore, there is almost no occurrence of reduced stress in the return bend 30, and no inclination occurs at the connection with the U pipe 18 which is the base end of the return bend 30, so that the deformation at this connection is eliminated. No accidents occur.

Further, as shown in FIG.
If the center portion of Ob is formed in a bellows shape and the return bend 30 is made more flexible by the bellows portion 32, the contraction stress can be more absorbed.

[0073]

As described above, according to the present invention, there is provided a heat exchanger in which a fin is bent so that a space of a notch portion of the fin is narrowed. A vertical side is provided, and a jig is hooked on the jig to insert the U-pipe and expand the pipe, so that the bulging deformation of the notch accompanying the insertion and expansion of the U-pipe is prevented, It is possible to eliminate the bending of the U-pipe and accurately determine the bending angle of the fin, thereby achieving effects such as improvement in heat exchange performance and reliability.

[0074] Incidentally, a heat exchanger for bending the fins in the space narrow Bamaru so notches of the fins, return bends across the cutout portion can absorb the contraction stress accompanying the bending of the fins, thus the This prevents deformation of the connection between the return bend and the U-pipe and the return bend itself , resulting in improved heat exchange performance and reliability.
You .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an air conditioner indoor unit provided with a heat exchanger, showing one embodiment of the present invention.

FIG. 2A is an enlarged view of a part of a fin and a jig for preventing deformation according to the embodiment. (B) is a front view of the whole fin and a part of the deformation preventing jig.

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

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

FIG. 5A is a front view of a return bend according to another embodiment. (B) is a front view of a part of the formed 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 fin, 9 notch, 5 heat exchanger, 18 U pipe, 19, 20, 30 return bend, 20a
Legs (of the return bend), 31 ... bellows (of the return bend).

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shinji Kurata 336 Tatehara, Fuji City, Shizuoka Prefecture Inside the Toshiba Fuji Plant (56) References JP-A-5-322468 (JP, A) JP-A-5-164348 (JP, A) JP-A-4-316931 (JP, A) JP-A-4-20793 (JP, A) JP-A-62-227536 (JP, A) JP-A-48-37949 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) F28F 1/32 B21D 53/08 F24F 1/00

Claims (2)

(57) [Claims] 1. 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, wherein a notch is formed together with a hole for inserting the pipe. A fin stacking step of stacking a plurality of the fins, a U pipe insertion step of inserting the U pipe into the stacked fins, an expanding step of expanding the inserted U pipe, a notch space of the stacked fins A method for manufacturing a heat exchanger, comprising: a bending step of bending a fin so as to reduce the width of the fin, wherein the U pipe insertion step and the pipe expansion step are performed by inserting a jig for preventing deformation into a notch of the fin. Method of manufacturing a heat exchanger. 2. The notch provided in the fin,
The fin is formed so as to have a pair of sides substantially perpendicular to the longitudinal side of the fin and parallel to each other. The jig for preventing deformation is inserted between the parallel sides of the notch. The method for manufacturing a heat exchanger according to claim 1, further comprising: