JP3369037B2 - Flare expansion aid for heat exchanger - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flare pipe expanding aid for a heat exchanger, and more particularly, to a primary member by press-fitting a pipe expanding mandrel into a heat transfer pipe of a heat exchanger used for an air conditioner, a cooler or the like. The present invention relates to a flare expansion aid for a heat exchanger used when press-fitting a flare punch for performing at least a secondary expansion into a tube opening of a heat transfer tube that has been expanded.

[0002]

Conventionally, as shown in FIG. 7 (a), a heat exchanger has been inserted into each of a plurality of heat radiating fins 2 and is located on one end side of the heat radiating fin 2 end plate. From the tube opening 3b of the projecting portion 3a of the heat transfer tube 3 protruding with a predetermined dimension from 8, the expansion pipe billet 4a for primary expansion is attached to one end side, and the other end side is Japanese Patent Publication No. 1-16213.
Manufactured by press-fitting a tube-expanding mandrel 4 mounted on a tube-expanding device (not shown) or the like described in Japanese Patent Laid-Open No. 10-28, to primary expand the heat transfer tube 3, and integrally fix the heat radiation fins 2 to the heat transfer tube 3. However, the heat exchanger 1 before pipe expansion is assembled by inserting a predetermined number of heat transfer tubes 3 into a plurality of holes (not shown) formed in the radiation fins 2 in a predetermined pattern in advance. Therefore, the outer diameter of the heat transfer tube 3 inserted into the heat radiation fin 2 is naturally smaller than the inner diameter of the hole formed in the heat radiation fin. Therefore, the heat transfer tube 3 and the heat radiation are not used. The fin 2 does not have a sufficiently close contact state before the primary tube expansion, and the heat exchanger 1 itself is in an extremely unstable state.

Therefore, as shown in FIG. 2B, the mandrel 4 for expanding the tube is press-fitted (arrow E) from the tube opening 3b of the projecting portion 3a of the heat transfer tube 3 to expand the heat transfer tube 3 for the primary expansion. The heat transfer tube 3
When the radiating fins 2 are fixed to the outer peripheral portion of the pipe, the heat transfer pipe 3 not only shrinks in its entire length in the pipe expanding direction of the pipe expanding mandrel 4 (arrow D) due to the material sink through the primary pipe expanding, Since the exchanger 1 itself has an extremely unstable state, the heat transfer tube 3 is inclined in a direction intersecting the tube expansion direction due to distortion due to material sink, and the axis of the heat transfer tube (arrow A) is expanded. In some cases, misalignment (arrow C) may occur without matching the axis of No. 4 (arrow B). In addition, the tube opening of the heat transfer tube 3 that has been subjected to the primary expansion as described above.
3b is subjected to flare processing as a secondary expansion pipe for attaching a substantially U-shaped connection pipe (not shown) for connecting the respective heat transfer pipes 3 which are normally expanded in a predetermined pattern, by brazing. Is common.

Therefore, as shown in FIG. 3C, flare processing for attaching a substantially U-shaped connecting pipe (not shown) is applied to the pipe opening 3b of the heat transfer pipe 3 after the primary expansion. Therefore, the flare forming portion 5a for flare processing as a secondary pipe is located on the other end side of the pipe expanding mandrel 4 and is slidably fitted on the pipe expanding mandrel 4 and is attached to the tip side thereof as a secondary pipe.
When press-fitting the flare punch 5 equipped with the heat transfer tube 3 into the tube mouth 3b of the heat transfer tube 3, if the heat transfer tube 3 is inclined in a direction intersecting with the tube expansion direction due to the distortion due to the material sink, it moves forward (arrow F ) The tip peripheral edge portion 5b of the flare forming portion 5a of the flare punch 5 bites the pipe opening peripheral portion 3c of the pipe opening 3b of the heat transfer tube 3 to which the primary expansion has been performed, and the galling deformation portion 9 is attached to the pipe opening 3b. In some cases, the galling deformation portion 9 may directly cause the leakage of the cooling liquid after brazing the substantially U-shaped connecting pipe (not shown) to the flared pipe port 3b. There was a very serious problem of becoming.

Therefore, the present invention solves the above-mentioned problems, and a predetermined flare punch is provided at the mouth of a heat transfer tube having a primary expansion tube so as to perform flare processing as at least a secondary expansion tube. In the case of press fitting into the mouth, even if the heat transfer tube is tilted in a direction intersecting with the expansion direction due to distortion due to material sink through the primary expansion due to press fitting of the expanding mandrel, the flare punch tip peripheral edge A portion of the flare punch is guided to the inside of the mouth of the heat transfer tube while preventing the portion from abutting the edge of the heat transfer tube and rubbing the mouth of the heat transfer tube. It is an object of the present invention to provide an extremely excellent flare tube expanding aid for a heat exchanger that can be surely applied to the mouth.

[0006]

In order to solve the above-mentioned problems, the present invention invents a flare expansion aid for a heat exchanger that is completely new and takes the following means.

[0007]

That is, according to the present invention, the mandrel shaft 4b has a pipe expanding billet 4a for primary pipe expansion on one end side, and a flare punch 5 capable of at least secondary pipe expansion slidably provided on the other end side. The flare tube expanding aid body 7a is formed from a tubular body movably fitted between the tube expanding billet 4a and the flare punch 5, and the flare tube expanding assist tool body 7a performs primary tube expansion through the tube expanding billet 4a. Since at least a part of the flare expansion aid main body 7a is inserted into the tube opening 3b of the heat transfer tube 3 of the heat exchanger 1 that can be locked to the tube opening 3b, the primary tube expansion Even if the heat transfer tube 3 has a core misalignment due to distortion due to material sink through the tube mouth 3b
It is possible to reliably prevent the inclined port opening peripheral edge portion 3c of the heat transfer tube 3 from coming into contact with the peripheral surface portion of the mandrel shaft 4b through the flare expansion assisting tool main body 7a locked to.

Therefore, the tip peripheral edge portion 5b of the flare punch 5 that advances to the tube mouth 3b to carry out flare tube expansion always comes into contact with the rear end of the flare tube expansion aid main body 7a locked to the tube opening 3b, and the flare tube expansion is performed. While the auxiliary tool main body 7a is being pressed and moved, the auxiliary tool main body 7a is guided into the heat transfer tube 3 together with the flare expansion auxiliary tool main body 7a, and therefore the tip peripheral edge portion 5b of the flare punch 5 contacts the pipe peripheral edge portion 3c of the pipe opening 3b. There is an advantage that desired flare processing can be easily and surely applied to the tube mouth 3b through the flare forming portion 5a of the flare punch 5 while surely preventing the contact.

Further, according to the present invention, the flare expansion aid main body 7a
Since the bulging portion 7b having an arcuate surface capable of abutting on the tube opening peripheral edge portion 3c of the heat transfer tube 3 is provided on the outer peripheral surface of the heat transfer tube 3, the heat transfer tube is distorted by the material sink through the primary expansion tube. Even when 3 has a misalignment, the tube opening peripheral edge portion 3c of the heat transfer tube 3 inclined via the flare expansion aid body 7a locked to the tube opening 3b via the bulging portion 7b is the peripheral surface portion of the mandrel shaft 4b. Not only can it be reliably prevented from coming into contact with the flare, but also the peripheral edge of the tip of the flare punch 5 that advances to the tube mouth 3b to perform flare expansion.
5b is always in contact with the rear end of the flare tube expanding aid body 7a locked in the tube mouth 3b, and is guided into the heat transfer tube 3 together with the flare tube expanding aid body 7a while pressing and moving the flare tube expanding aid body 7a. At this time, the flare expansion assisting tool main body 7a can be more smoothly inserted through the arc surface of the bulging portion 7b.
Can be inserted into the heat transfer tube 3. Therefore, even in this case, it is possible to surely prevent the tip peripheral edge portion 5b of the flare punch 5 from coming into contact with the pipe mouth peripheral edge portion 3c of the pipe mouth 3b, and to perform the desired flare processing on the pipe mouth 3b through the flare forming portion 5a of the flare punch 5. Has an advantage that it can be applied easily and surely.

Further, according to the present invention, since the bulging portion 7b is annularly provided on the outer peripheral surface of the flare expansion aid main body 7a, the peripheral edge portion of the flare punch 5 which advances to the pipe opening 3b for performing flare expansion. 5b is always in contact with the rear end of the flare tube expanding aid body 7a locked in the tube mouth 3b, and is guided into the heat transfer tube 3 together with the flare tube expanding aid body 7a while pressing and moving the flare tube expanding aid body 7a. In doing so, the flare tube expansion assisting tool body 7a can be smoothly and surely transferred from the pipe opening 3b through the arc surface of the bulging portion 7b annularly provided on the outer peripheral surface of the flare tube expanding aid tool body 7a from the pipe port 3b. 3 has the advantage that it can be inserted.

Further, according to the present invention, the flare expansion aid main body 7a
Since a plurality of projections 7e having arcuate surfaces capable of contacting the tube opening peripheral edge 3c of the heat transfer tube 3 are provided on the outer peripheral surface of the flare expansion assisting tool main body 7a via the projections 7e. Can be locked to the tube opening 3b of the heat transfer tube 3 having the primary expansion. Therefore, even if the heat transfer tube 3 has a misalignment through the primary tube expansion, the flare of the heat transfer tube 3 inclined through the flare tube expansion aid main body 7a locked to the tube opening 3b through the bulging portion 7b. Not only can the part 3c be reliably prevented from coming into contact with the peripheral surface part of the mandrel shaft 4b, but the tip peripheral edge part 5b of the flare punch 5 that advances to the tube mouth 3b to perform flare expansion is always engaged with the tube mouth 3b. The flare pipe expanding aid body 7a is brought into contact with the rear end of the stopped flare pipe expanding aid body 7a, and the flare pipe expanding aid body 7a is pressed and moved while being guided into the heat transfer tube 3 together with the flare pipe expanding aid body 7a. A plurality of protrusions provided on the outer peripheral surface of the ingredient body 7a
There is an advantage that the flare tube expansion assisting tool main body 7a can be inserted into the heat transfer tube 3 from the tube opening 3b more smoothly and surely via the arc surface of 7e.

Further, according to the present invention, the flare expansion aid main body 7a
In addition, since the inclined surface portion 7c that is tapered toward the opposing heat transfer tube 3 side is provided, the heat transfer tube in which the flare tube expansion assisting tool main body 7a is primarily expanded through the inclined surface portion 7c. It can be locked to the tube mouth 3b of No. 3. Therefore, even if the heat transfer tube 3 has a misalignment through the primary tube, the peripheral portion of the heat transfer tube 3 inclined through the flare tube expansion auxiliary tool body 7a locked to the tube opening 3b through the inclined surface portion 7c. 3c is the mandrel axis
Not only can it surely be prevented from coming into contact with the peripheral surface of 4b, but the tip peripheral edge portion 5b of the flare punch 5 that advances to the tube mouth 3b in order to perform flare tube expansion is always flared by the tube opening 3b. Formed on the flare tube expansion assisting tool body 7a when the flare tube expanding aid tool body 7a is guided by the flare tube expanding assisting tool body 7a into the heat transfer tube 3 together with the flare tube expanding aid tool body 7a while pressing the flare tube expanding aid tool body 7a. There is an advantage that the flare tube expansion assisting tool main body 7a can be inserted into the heat transfer tube 3 through the tube opening 3b more smoothly and reliably via the tapered inclined surface portion 7c.

[0014]

DETAILED DESCRIPTION OF THE INVENTION

<First Embodiment> Hereinafter, a first embodiment for carrying out a flare expansion aid for a heat exchanger according to the present invention will be described with reference to the drawings. The description of the same parts as the configuration will be omitted below.

In FIG. 1, reference numeral 7 denotes a flare expanding aid which is movably fitted on the mandrel shaft 4b between the expanding billet 4a and flare punch 5, and 7a is a flare expanding aid body composed of a tubular body. 7a, as shown in FIG. 2, the main body 7a is provided with a single cutout groove 7d along the entire length of the main body 7a, and the outer peripheral surface of the main body 7a on the flare punch 5 side has an annular surface. The bulging portion 7b is provided.

As shown in FIG. 3, the flare expansion aid main body 7a made of the above-mentioned tubular body has an outer diameter (arrow M) on the expansion billet 4a side from the maximum outer diameter (arrow O) of the expansion billet 4a. The outer diameter (arrow N) on the flare punch 5 side is smaller than the outer diameter (arrow R) of the tip peripheral edge portion 5b of the flare punch 5,
In addition, the maximum outer diameter (arrow P) of the annular bulging portion 7b formed on the outer peripheral surface of the main body 7a is smaller than the outer diameter (arrow Q) of the flare forming portion 5a. 3b of the heat transfer tube 3 expanded by the primary expansion through
The size is preset so that it can be locked to.

The flare tube expanding aid for the heat exchanger according to the first embodiment has the above-described structure. Next, the flare tube expanding aid is used to form the primary tube expansion and the secondary tube expansion in the heat transfer tube 3 of the heat exchanger 1. A description will be given of the case of performing flare processing as.

First, as shown in FIG. 3, the tube-expanding mandrel 4 mounted on a tube-expanding device (not shown) is press-fitted (arrow I) from the tube opening 3b of the heat-transfer tube 3 to make the heat-transfer tube 3 primary. The pipe is expanded, but at this time, the flare expansion aid main body 7a is also expanded billet 4a.
A part of the main body 7a on the side is inserted into the tube opening 3b of the heat transfer tube 3 having the primary expansion (arrow J), and is locked to the tube opening 3b through the annular bulging portion 7b. It will be.

Therefore, even if the heat transfer tube 3 has a misalignment due to the distortion due to the material sink through the primary tube expansion and is inclined so as to purify the tube opening 3b, the flare tube expanding auxiliary tool locked to the tube opening 3b. The peripheral portion 3c of the heat transfer tube 3 inclined through the main body 7a
Can be reliably prevented from coming into contact with the peripheral surface portion of the mandrel shaft 4b.

Thereafter, as shown in FIG. 4, the flare punch 5 is moved forward (arrow K) through a pipe expanding device (not shown) or the like in order to perform flare expansion on the tube opening 3b of the heat transfer tube 3 which has been subjected to primary expansion. ), The flare punch 5 advancing to the tube mouth 3b is
The tip peripheral edge portion 5b of the flare punch 5 is always brought into contact with the rear end of the flare expansion assisting tool main body 7a locked to the tube opening 3b, and
While the flare pipe expanding aid body 7a is pressed and moved (arrow L), the flare pipe expanding aid body 7a is guided into the heat transfer tube 3 together with the flare pipe expanding aid body 7a. The flare expansion assisting tool main body 7a can be surely prevented from coming into contact with the peripheral portion 3c of the pipe mouth, and the desired flare processing 6 can be easily performed on the pipe mouth 3b through the flare forming portion 5a of the flare punch 5. In addition, there is an advantage that it can be surely applied.

Further, since the flare expansion aid main body 7a made of the above-mentioned tubular body is provided with a single cutout groove 7d along the entire length direction of the main body 7a, the auxiliary tool main body 7a is externally fitted. Depending on the type of mandrel shaft 4b
Even if the outer diameter of 4b is changed, the inner diameter of the auxiliary tool main body 7a can be expanded or contracted via the notch groove 7d, and there is an advantage that versatility in use can be greatly improved.

<Second Embodiment> In the above first embodiment, the outer peripheral surface of the flare expansion aid main body 7a can be brought into contact with the peripheral portion 3c of the heat transfer tube 3 having the primary expansion. Although the annular bulging portion 7b having a circular arc surface is provided, it is not always necessary to provide the annular bulging portion 7b, and as shown in FIG. 5A, the heat transfer tube is provided on the outer peripheral surface of the flare expansion aid main body 7a. 3 may have a plurality of projections 7e having an arc surface (hemispherical shape) capable of contacting the peripheral portion 3c of the tube opening, and the plurality of projections 7e may be provided at predetermined intervals, as shown in FIG. The projecting portion 7e of the heat transfer tube 3 faces
It may be formed in the shape of an inverted water drop that is tapered toward the side, and in any case, the flare tube expansion assisting device main body 7a is subjected to primary tube expansion through the protrusion 7e. In addition to being able to lock the heat transfer tube 3 to the tube opening 3b, even if the heat transfer tube 3 is misaligned through the primary expansion tube, the tube opening 3b
Flare tube expansion aid main body locked to the plurality of protrusions 7e
There is an advantage that it is possible to reliably prevent the peripheral portion 3c of the heat transfer tube 3 inclined by 7a from coming into contact with the peripheral surface portion of the mandrel shaft 4b.

Therefore, the tip peripheral edge portion 5b of the flare punch 5 that advances to the tube mouth 3b to perform the flare tube expansion in the same manner as described above is surely secured to the tube mouth 3b through the plurality of projections 7e. 7a abutting on the rear end of the flare tube expansion aid body
When the flare pipe expanding aid main body 7a is guided along with the flare pipe expanding assisting device main body 7a into the heat transfer tube 3, the flare pipe expanding aid main body
There is an advantage that the flare expansion aid main body 7a can be inserted into the heat transfer tube 3 from the tube opening 3b more smoothly and surely through the arcuate surfaces of the plurality of protrusions 7e provided on the outer peripheral surface of the 7a. .

<Third Embodiment> Further, in each of the above-mentioned embodiments, the flared tube expanding aid main body 7a has an annular bulging portion 7b having a circular arc surface and a plurality of protrusions 7e on the outer peripheral surface thereof. As shown in FIG. 6C, a step portion 7f having an arc surface capable of engaging with the tube opening 3b of the heat transfer tube 3 in which the primary expansion has been performed is formed on the flare expansion aid main body 7a. Even in this case, the tip peripheral edge portion 5b of the flare punch 5 is always brought into contact with the rear end of the flare pipe expanding aid body 7a locked to the pipe mouth 3b through the step 7f, and the flare pipe expanding aid body 7a. When being guided into the heat transfer tube 3 together with the flare tube expansion assisting tool body 7a while being pressed and moved, it is possible to smoothly and securely through the arc surface of the stepped portion 7f provided on the flare tube expansion assisting tool body 7a. There is an advantage that the flare expansion aid main body 7a can be inserted into the heat transfer tube 3 through the tube opening 3b.

<Fourth Embodiment> Furthermore, the structure for smoothly inserting the flare expansion aid main body 7a into the heat transfer tube 3 from the opening 3b of the heat transfer tube 3 is by no means limited. For example, FIG.
As shown in FIG. 7, the flare expansion aid main body 7a is provided with an inclined surface portion 7c which is tapered toward the opposing heat transfer tube 3 side.
7a may be provided to have a substantially wedge shape in side view, and further, as shown in the same figure (b), an inclined surface portion 7c may be formed on the entire main body 7a to have a substantially inverted trapezoidal shape in side view, Further, as shown in FIG. 3C, an inclined surface portion 7c tapered toward the opposing heat transfer tube 3 side may be formed on the outer periphery of the tip of the main body 7a. In any case, the inclined surface portion 7c The flare tube expansion aid main body 7a through the pipe opening 3b of the heat transfer tube 3 to which the primary tube expansion is applied.
Can be locked to.

Therefore, even if the heat transfer tube 3 has a misalignment through the primary tube expansion, the tube opening of the heat transfer tube 3 inclined through the flare tube expansion aid main body 7a locked to the tube opening 3b by the inclined surface portion 7c. Not only can the peripheral edge portion 3c be reliably prevented from coming into contact with the peripheral surface portion of the mandrel shaft 4b, but the peripheral edge portion of the flare punch 5 that advances to the tube mouth 3b for flare expansion.
5b is always in contact with the rear end of the flare tube expanding aid main body 7a locked to the tube opening 3b through the inclined surface portion 7c, and the flare tube expanding assisting tool body 7a is pressed and moved.
When being guided into the heat transfer tube 3 together with the heat transfer tube, the flare tube expansion assisting tool body 7a is smoothly and surely transferred from the pipe port 3b through the tapered inclined surface portion 7c formed on the flare tube expanding assisting tool body 7a. 3 has the advantage that it can be inserted.

Further, in each of the above-mentioned embodiments, the heat exchanger is composed of a plurality of heat radiation fins and an end plate, but the end plate is not always an essential requirement.
What is essential is that the heat exchanger is formed into a desired shape by superimposing a plurality of radiating fins, and the external shape of the heat exchanger, the number of radiating fins to be superposed, and the heat transfer tube inserted into the radiating fins. Needless to say, the total number and the insertion pattern are not limited.

Furthermore, in each of the above-mentioned embodiments, the flare punch has a flare forming portion as a secondary expansion tube.
The flare punch may be a flare punch for secondary and tertiary flaring that enables secondary flare processing and tertiary flare processing, and the structure and function of the flare punch, and a pipe expanding device including the flare punch and the mandrel for expanding the pipe. The specific structure and type are not limited.

However, the point is to prevent the peripheral edge of the flare punch from coming into contact with the peripheral edge of the heat transfer tube,
If the flare expansion aid for guiding the tip peripheral portion of the flare punch into the tube mouth of the heat transfer tube is slidably provided on the mandrel shaft between the primary expansion billet of the expansion mandrel and the flare punch, Needless to say, the specific shape and function of the flare tube expanding aid are by no means limited.

[0030]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, the mandrel for expanding the pipe having the expanding billet for the primary expansion is press-fitted.
When pressurizing at least the flare punch capable of secondary expansion from the mouth of the heat transfer tube of the heat exchanger subjected to the secondary expansion,
The heat transfer tube is cored due to distortion caused by material sink through the tube.
Flare expansion aid that is locked at the mouth of the tube even if it has
Through the main body, the inclined peripheral edge of the heat transfer tube
It is possible to guide the peripheral edge of the flare punch into the tube mouth of the heat transfer tube while preventing the flare punch from coming into contact with the peripheral surface of the shaft.
Wear. Therefore, even if the heat transfer tube is tilted in the direction intersecting the tube expanding direction of the tube expanding mandrel due to the distortion of the material sink through the primary tube expansion due to the press-fitting of the tube expanding mandrel, the port opening of the tube is formed. It is extremely excellent in that the peripheral edge portion can be reliably guided into the pipe mouth without being bitten by the peripheral portion of the tip of the flare punch, and the desired flare processing can be easily and surely applied to the pipe mouth via the flare forming portion of the flare punch. The present invention has a special effect of being able to provide a flare expansion aid for a heat exchanger.

[Brief description of drawings]

FIG. 1 is an enlarged partial sectional view of an essential part showing a usage state of a flare tube expanding aid for a heat exchanger of the present invention.

FIG. 2 shows a flare tube expanding aid for a heat exchanger of the present invention,
The same figure (a) is a front view, the same figure (b) is H-H of the same figure (a).
FIG.

FIG. 3 is an enlarged partial sectional view of an essential part showing a usage state of the flare expansion assisting tool for the heat exchanger of the present invention at the time of primary expansion by the first embodiment.

FIG. 4 is an enlarged partial sectional view of an essential part showing a usage state during flare tube expansion according to the first embodiment of the flare tube expansion aid of the heat exchanger of the present invention.

FIG. 5 shows another embodiment of the flare tube expanding aid of the heat exchanger, and FIGS. 5A, 5B, and 5C are side views of the flare tube expanding aid.

FIG. 6 shows another embodiment of the flare tube expanding aid for the heat exchanger, and FIGS. 6A, 6B, and 6C are side views of the flare tube expanding aid.

FIG. 7 shows a manufacturing process of a conventional heat exchanger, in which (A), (B), and (C) are enlarged partial cross-sectional views of a main part.

[Explanation of symbols]

1 ... Heat exchanger 2 ... Radiating fin 3 ... Heat transfer tube 3a ... projection 3b ... tube mouth 3c… Edge of pipe mouth 4 ... Primary pipe expanding mandrel 4a ... Expansion billet 4b ... Mandrel axis 5 ... flare punch 5a ... flare formation part 5b ... Tip peripheral part 6 ... flare part 7 ... Flare tube expansion aid 7a ... Flare expansion aid body 7b ... Bulging part 7c… Sloping surface 8 ... End plate 9… Gnailing deformation part A ... Virtual line of heat transfer tube axis B: Virtual line of the shaft center of the primary expansion mandrel

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Claims (4)

(57) [Claims] 1. A pipe expanding billet (4a) for primary pipe expansion on one end side.
And has at least a secondary expandable frame on the other end side.
Mandrel shaft with a slidable approach (5)
Transfer between the expansion billet (4a) and flare punch (5) in (4b).
From the movably fitted tubular body to the flare expansion aid body (7
a) is formed, and the flare expansion aid body (7a) is
Heat exchange with primary expansion via expansion billet (4a)
The flare expansion aid in the tube mouth (3b) of the heat transfer tube (3) of the vessel (1).
Insert at least a part of the body (7a) into the tube mouth (3b).
The flare expansion aid body (7
The outer peripheral surface of a) can come into contact with the peripheral portion (3c) of the heat transfer tube (3).
A flare pipe expanding aid for a heat exchanger, characterized in that it is provided with a bulging portion (7b) having an effective arc surface . 2. The main body of the flare tube expansion assisting device, wherein the bulging portion (7b) is
It is characterized in that it is provided in an annular shape on the outer peripheral surface of (7a)
The flare tube expanding aid for a heat exchanger according to claim 1 . 3. The bulged portion (7b) is composed of a plurality of protrusions (7e).
The flare pipe expanding aid for a heat exchanger according to claim 1, wherein 4. An expansion billet (4a) for primary expansion on one end side.
And has at least a secondary expandable frame on the other end side.
Mandrel shaft with a slidable approach (5)
Transfer between the expansion billet (4a) and flare punch (5) in (4b).
From the movably fitted tubular body to the flare expansion aid body (7
a) is formed, and the flare expansion aid body (7a) is
Heat exchange with primary expansion via expansion billet (4a)
The flare expansion aid in the tube mouth (3b) of the heat transfer tube (3) of the vessel (1).
Insert at least a part of the body (7a) into the tube mouth (3b).
The flare expansion aid body (7
A flare expansion aid for a heat exchanger, characterized in that a) is provided with an inclined surface portion (7c) which is formed to be tapered toward the heat transfer tube (3) side facing the a).