JP2989532B2 - How to make a cross fin tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an improved cross fin tube.
Relates to the manufacturing method, the heat transfer tube caused to pipe expansion secured to the aluminum plate fins obtained by pressing from Plate fin material especially, when forming the cross fin tube, that allowed to elicit fin pitch disturbances The present invention relates to a method for manufacturing a cross-fin tube without any problem.

[0002]

2. Description of the Related Art Conventionally, heat exchangers that operate as evaporators or condensers have been used in air conditioners such as home air conditioners, automobile air conditioners, package air conditioners, and refrigerators. Among them, a cross fin tube heat exchanger (plate fin tube heat exchanger) is most commonly used for a household indoor air conditioner and a commercial package air conditioner. The cross fin tube constituting the cross fin tube heat exchanger includes an aluminum plate fin on the air side and a heat transfer tube (copper tube) on the refrigerant side. More specifically, first, from an aluminum plate fin material, an aluminum plate fin in which a plurality of predetermined mounting holes are formed is obtained by press working, and then the obtained aluminum plate fins are laminated, The heat transfer tube can be obtained by inserting a separately manufactured heat transfer tube into the perforated hole and then expanding and fixing the heat transfer tube to an aluminum plate fin.

By the way, in recent years, in order to improve the heat exchange efficiency of the cross fin tube heat exchanger, the interval between the laminated aluminum plate fins, that is, the fin pitch of the cross fin tube, tends to be small. When the fin pitch is reduced, the so-called fin pitch disorder (Abeck phenomenon) is liable to occur when the aluminum plate fins adhere to each other when the heat transfer tube is expanded and fixed. When this fin pitch disturbance is caused, not only is the appearance unfavorable, but also because the water droplets easily accumulate, the ventilation resistance of the air passing between the fins is significantly increased, and the heat exchange efficiency is rather reduced. it is the problem of low below occurs.

In general, the fin pitch disturbance is more likely to occur as the fin pitch becomes smaller, as the hardness of the aluminum plate fin becomes harder, and further, as the expansion ratio becomes larger, It is considered that the occurrence of fin pitch disturbance is suppressed by using a soft material for the aluminum plate fins, increasing the fin pitch, or suppressing the expansion ratio. However, when the fin pitch is increased, the total surface area of the fins is reduced, and the heat exchange efficiency is reduced. Therefore, such a measure is not an essential solution. Also, plate fins can be roughly classified into a draw method and a drawless method (ironing method). In recent years, a drawless method using a thin and hard material has been adopted to reduce costs. In the use of such a hard material, from the viewpoint of improvement in handling properties, improvement in heat exchange efficiency due to increase in the tightening force of the heat transfer tube, measures to adopt the soft material described above are desirable. There is no. Furthermore, when the expansion ratio is reduced, the contact between the aluminum plate fins and the heat transfer tubes tends to be insufficient, which causes a problem that the heat exchange efficiency is reduced.

As described above, various measures have been considered to prevent or suppress the occurrence of the fin pitch disturbance. However, any of the methods is intended to avoid the occurrence of the fin pitch disturbance. In addition, since it is not possible to avoid a decrease in heat exchange efficiency, it cannot be said that this is an effective method. Therefore, without reducing the heat exchange efficiency, it is possible to advantageously prevent the occurrence of fin pitch disturbance. The development of aluminum plate fin materials is desired.

The inventors of the present invention have conducted various studies to find the cause of the above-mentioned fin pitch disturbance, and found that the fin pitch disturbance is caused by the following mechanism. Findings were obtained.

That is, first, in FIG. 1, a heat transfer tube 8 is inserted through an assembling hole 6 in which a cylindrical collar portion 4 of a plurality of aluminum plate fins 2 is provided. The state is shown. The collar portion 4 is provided so as to extend vertically at a predetermined height with respect to the aluminum plate fin 2,
At its tip, a curl (flare) portion 10 is formed in which the inner surface of the collar portion 4 is warped. Then, in this state, the expander (plug) 12
When the heat transfer tube 8 is expanded by inserting the heat transfer tube 8, the outer diameter of the heat transfer tube 8 becomes larger than the inner diameter of the collar portion 4 of the assembling hole 6, so that the inner diameter of the assembling hole 6 (the collar portion 4) also increases. , With the outer diameter of the heat transfer tube 8. At this time, since the thickness of the aluminum plate fins 2 is very thin, usually 0.10 mm to 0.12 mm, only the deformation in the plane, that is, the change in the inner diameter of the assembling hole 6 is obtained. Then, since it cannot be absorbed, out-of-plane deformation occurs.

This out-of-plane deformation is usually more stable when the root angle α of the collar portion 4 is made obtuse. Therefore, each aluminum plate fin 2 is shown in FIG.
As shown in FIG. 2, the collar portion 4 should be deformed so as to increase the root angle α. However, in practice, as shown in FIG. 2B, the root angle α is often made obtuse and acute. Are mixed. In this way, a part of the root angle α, which should be obtuse, should become acute, so that the fin pitch becomes larger or smaller. It is disturbed.

The reason why the obtuse angle and the acute angle of the root angle α are mixed as described above is that when the heat transfer tubes 8 are expanded while the aluminum plate fins 2 are stacked, as the expansion proceeds, It is conceivable that a compression reaction force is generated in the aluminum plate fins 2 and expansion is performed under an unusual state. More specifically, the heat transfer tube 8 is expanded by inserting the expander 12, but in general, when the tube diameter is increased by the expansion, the length in the tube axis direction is reduced. Then, the contraction of the heat transfer tube in the tube axis direction is transmitted to the plate fins in the portion where the tube expansion has not been performed yet, and the collar portion 4 provided in the plate fin assembling hole 6 located in this portion. , Are subjected to compressive deformation in the tube axis direction, that is, in the height direction. However, the curl part 10
When receiving such a compressive deformation, a repulsive force (compression reaction force) that attempts to restore the deformation is generated. Therefore, the fins other than the aluminum plate fin to be expanded first are expanded while generating some compression reaction force (the inner diameter of the collar is expanded).

[0010] As described above, when the heat transfer tube is expanded, the aluminum plate fins, besides the radial force of the mounting hole,
Although it is subject to the action of the compression reaction force, the amount of compressive deformation is small and the compression reaction force is small at the collar portion of the aluminum plate fin arranged at the part where the tube is initially expanded, so the fins are opposed to the compression force. However, when the root angle of the collar portion is deformed in a direction in which the root angle becomes obtuse, the expansion of the tube proceeds and the amount of compression deformation and the compression reaction force increase. The root angle is deformed in a direction to become acute, and the fin pitch is disturbed.

As a result of further studies by the present inventors, when the heat transfer tube is expanded, a compression reaction force due to the compression deformation is generated in the collar portion. It has been found that, at the contact portion with the aluminum plate fin located immediately below, it tends to be reduced due to slippage. That is, since the aluminum plate fins arranged above and below slide relatively to each other, the compression reaction force is reduced.
However, when the frictional resistance at the contact portion is large, the sliding reaction cannot be performed.
It will remain as it is.

As described above, the fin pitch disturbance is caused by expanding the heat transfer tube in a state where the collar portion of the aluminum plate fin in the unexpanded portion has a compression deformation and a compression reaction force. Therefore, it was concluded that in order to suppress or prevent the occurrence of the fin pitch disturbance, it is sufficient to reduce the compression reaction force, and it is effective to reduce the friction between the aluminum plate fins. is there.

[0013]

Here, the present invention has been completed based on the above-mentioned findings, and the problem to be solved is to improve the slipperiness of the surface of an aluminum plate fin material by improving the slipperiness. After inserting the heat transfer tube into a predetermined mounting hole formed in the aluminum plate fin obtained by pressing the fin material, the fin pitch is not disturbed when the heat transfer tube is expanded and fixed to the aluminum plate fin. so
And a method for manufacturing a cross fin tube .

[0014]

SOLUTION] In order to solve such problems, the present invention, while assembly bore formed by providing a cylindrical collar portion of the predetermined height around hole Ru formed a plurality, of the collar portion
The curled part is in a state where the tip warps its inner surface.
Using aluminum plate fins
One or more of the minium plate fins
Contact each other so that they match,
Insert the heat transfer tube through the matching mounting hole
Then, by inserting an expander into the heat transfer tube,
Expand the heat transfer tube, and
The heat transfer tube and aluminum plate
Cross fin integrated with rate fin
In manufacturing the tube, a hydrophilic film is formed by a hydrophilic surface treatment over the entire surface, and a water-soluble polyether and / or
Or its esterified product or alkali metal of higher fatty acid
A layer formed by applying a water-soluble lubricant made of salt is further formed by using an aluminum plate fin material formed ,
Pressing to obtain the aluminum plate fin
To assemble the heat transfer tubes by the pipe expansion operation.
This is caused when the tube is expanded by inserting the expander.
Suppress or prevent fin pitch disturbance
The gist is a method for manufacturing a cross fin tube characterized by the following.

That is, in the aluminum plate fin material used in the present invention, a predetermined water-soluble lubricant is applied to the outer surface of the hydrophilic film formed by the hydrophilic surface treatment. When the aluminum fins obtained by pressing the plate fin material are laminated, the frictional resistance between the plate fins is effectively reduced because the layer formed is further formed. Since the frictional force exerted between the aluminum plate fins is small, the heat transfer tube is inserted into a predetermined mounting hole provided in the aluminum plate fin, and the heat transfer tube is expanded. Thus, when the heat transfer tube is fixed to the aluminum plate fin, the aluminum plate fin is compressed and deformed. Receiving also becomes the fins each other slide each other, it become as occurrence of compression reactive force due to the compressive deformation Te following may be advantageously suppressed.

Since the layer of the water-soluble lubricant is formed on the aluminum plate fin material before the press working, the lubricating property makes it possible to obtain good aluminum plate fins by performing the press working. Not only can formability be obtained, but also the heat transfer tube can be smoothly inserted when the heat transfer tube is inserted into the obtained aluminum plate fin.

Incidentally, since such a lubricant layer is water-soluble, it can be easily removed, for example, in an airtightness test conducted after the brazing step after expanding the heat transfer tube. No special removal steps are required. More specifically, such an airtight test is to check the airtightness of the heat transfer tube by immersing the obtained cross fin tube in water, and at this time, the water-soluble lubricant layer is dissolved in water. Thus, it can be easily removed. As described above, since the water-soluble lubricant can be removed without performing a special removal step, even if a layer of the water-soluble lubricant is present, the hydrophilic film formed thereunder is formed. It naturally comes out on the surface, whereby the action of the hydrophilic film is effectively exerted. In the airtightness test as described above, even if the water-soluble lubricant layer is not completely removed, if the heat exchanger employing the obtained cross fin tube is used as an evaporator, the heat exchanger may be replaced with an aluminum plate fin. Means that water droplets generated by condensation of water vapor in the air will stick,
The water droplets cause the remaining water-soluble lubricant to be washed away, so that the underlying hydrophilic film can be advantageously exposed to the surface.

[0018]

[0019] Also, cross fin Chu in accordance with the present invention
According to a preferred aspect of the method of manufacturing a fin, the amount of the lubricant applied to the aluminum plate fin material,
It is in the range of 0.05 to 0.5 g / m ² .

[0020]

DETAILED DESCRIPTION OF THE INVENTION By the way, used in the present invention
In the aluminum plate fin material, a hydrophilic film is formed on the surface, and a predetermined water-soluble lubricant layer is further formed thereon.

As the material adopted for the aluminum plate fin material according to the present invention, any aluminum material conventionally used as a fin material can be used. Since a material having a high strength is used along with a reduction in thickness, a material having such a strength is advantageously used in the present invention.

Further, in the present invention, the hydrophilic surface treatment performed to form a hydrophilic film includes a conventionally known method, for example, Japanese Patent Application Laid-Open No.
JP-B-57-46000, JP-A-61-2278
No. 77, Japanese Patent Publication No. 6-73934, and the like can be adopted. Specifically,
Taking the method described in JP 73934 as an example,
The hydrophilic film is made of Me ₂ O · nSiO ₂ (where Me is
An alkali silicate represented by lithium, potassium, sodium or an amine); acrylamide;
(Meth) acrylamides such as methacrylamide, hydroxymethyl (meth) acrylamide and hydroxyethyl (meth) acrylamide; (meth) acrylates such as hydroxypropyl (meth) acrylate and hydroxyethyl (meth) acrylate; acrylic acid and methacrylic acid Such as polymers such as unsaturated carboxylic acids, or copolymers of these unsaturated compounds, or copolymers of these unsaturated compounds with other unsaturated compounds, or carboxyl groups or hydroxyl groups by hydrolysis or the like. A composite composition comprising a hydrophilic polymer compound into which an amino group or the like has been introduced is crosslinked with a crosslinking agent composed of ammonium zirconium carbonate or a zirconium complex compound, or a mixture thereof, and cured to form a composite coating. Can be formed In the case of performing the hydrophilic surface treatment, a conventionally known method is appropriately employed, for example, a method of coating the aluminum plate fin material according to a roll coater method.

In the aluminum plate fin material for a heat exchanger according to the present invention, a layer made of a water-soluble lubricant is further formed on the hydrophilic film as described above. Water-soluble lubricants are water-soluble,
Any material having excellent lubricity can be employed. As this water-soluble lubricant,
Specifically, polyethers such as polyethylene glycol, polypropylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxypropylene polyoxyethylene alkyl ether, polyoxypropylene polyoxyethylene glyceryl ether and / or esters thereof with terephthalic acid and the like And alkali metal salts of higher fatty acids such as sodium palmitate, potassium palmitate, sodium stearate, potassium stearate, sodium oleate and potassium oleate. The water-soluble lubricant is applied according to a conventionally known method, for example, a roll coater method, as in the case of the hydrophilic surface treatment.

Incidentally, such a water-soluble lubricant is usually used in 0.1 g.
It is used so as to have a coating amount of from 0.5 to 0.5 g / m ² . If the ratio is less than 0.05 g / m ² , the effect of the lubricant is not sufficient, and when the heat transfer tube is expanded and fixed to the aluminum plate fin obtained by press working, the fin pitch disturbance is caused. Is more likely to occur, and the ratio is 0.5 g / m ^2.
If the amount is larger than the above range, the lubricating effect is further improved, but the lubricant is more likely to be deposited on the roll of the roll coater.

Incidentally, the water-soluble lubricant layer is not necessarily formed on both surfaces, but is formed on the surface where the fins are in contact with each other, in other words, on the surface which is the inner surface of the cylindrical collar portion. If there is, there is no problem even if it is formed only on one side.

The surface of the aluminum plate fin material is required to have hydrophilicity and corrosion resistance. In general, the more hydrophilic the film, the lower the corrosion resistance. In the case of a plate fin material, before forming a hydrophilic film, in order to form a corrosion-resistant film on an underlayer, conventionally known various methods, for example, by performing a corrosion-resistant surface treatment by chemical conversion treatment or organic resin coating. No problem.

[0027]

EXAMPLES In order to clarify the present invention more specifically, some examples of the present invention will be shown below.
It goes without saying that the present invention is not subject to any restrictions by the description of such embodiments. In addition, in addition to the following examples, the present invention, in addition to the above-described specific description, various changes, corrections, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that improvements can be made.

First, the aluminum plate fin material for drawless and DOF (Dry Oil Fin Die) having a thickness of 0.10 mm is subjected to a degreasing treatment using a commercially available weak alkaline degreasing agent. A chemical conversion film mainly composed of phosphoric acid chromate was formed with a liquid composed of phosphoric acid and hydrofluoric acid. At this time, the amount of chromium in the chemical conversion film was 20 mg / m ² .

Next, 10 parts by weight of an alkali silicate (SiO ₂ : Na ₂ O = 5: 2) and acrylamide-acryl as a hydrophilic polymer were added to the aluminum plate fin material subjected to the chemical conversion treatment. Using a hydrophilic coating composition comprising 1 part by weight of an acid copolymer and 0.5 part by weight of ammonium zirconium carbonate as a cross-linking agent, coating was carried out with a roll coater, and then 20 parts by weight.
By performing a heat treatment at 0 ° C. for 20 seconds, a predetermined hydrophilic film was baked and cured. The amount of Si in the hydrophilic film was 0.1 g / m ² .

Then, following this hydrophilic surface treatment, a water-soluble lubricant shown in the following Table 1 is applied on the formed hydrophilic film by a roll coater method, and thereafter, 120 ° C. × 30 seconds. Table 1 below
The water-soluble lubricant layer was formed at the coating amount shown in (1).

The thus obtained aluminum plate fin material on which the hydrophilic film and the water-soluble lubricant layer were formed was applied to a 9.52 mmφ drawless mold (manufactured by Hidaka Seiki Co., Ltd.).
The height is 1.6m by pressing using
1 is formed with an assembling hole provided with a m collar portion.
Aluminum plate fins with ribs in eight rows were produced.

[0032]

[Table 1] * 1: Lubricant tends to accumulate on the roll coater.

Thereafter, a 9.52 mmφ heat transfer tube (copper tube with an inner groove) was inserted into the assembly hole of the obtained aluminum plate fin, and then 9.14 mm was inserted into the heat transfer tube.
By inserting a plug of φ, the heat transfer tube was expanded and fixed to an aluminum plate fin to produce a cross fin tube. The fin pitch disturbance of the cross fin tube thus obtained was examined, and the results are shown in Table 1 above. The expansion ratio (outer diameter expansion ratio) of the heat transfer tube was 4.6%, and the expansion speed was 50 mm / s. Further, only the aluminum plate fin according to Comparative Example 1 was washed with water to remove the water-soluble lubricant layer on the surface, and then the heat transfer tube was expanded.

As shown in Table 1, when the aluminum plate fin material of the example of the present invention was used, the fin pitch disturbance did not occur at all or hardly occurred, whereas the aluminum plate fin material of the comparative example did not. When a fin material was used, fin pitch disturbance occurred in all the cross fin tubes. Thus, it is easily understood that when a cross fin tube is manufactured using the aluminum plate fin material according to the present invention, the occurrence of fin pitch disturbance can be advantageously suppressed.

[0035]

As is apparent from the above description, the present invention can be used in a method for manufacturing a cross fin tube according to the present invention .
In the aluminum plate fin material, the heat transfer tube is inserted into the aluminum fin obtained by pressing the aluminum plate fin material, and even if the expanded tube is fixed, fin pitch disturbance is unlikely to occur. The heat exchanger employing the aluminum plate fin material has an excellent appearance and a very good heat exchange efficiency.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a state before expansion of a tube in which a heat transfer tube is inserted into a mounting hole of an aluminum plate fin.

FIGS. 2A and 2B are enlarged explanatory views of a main part showing arrangement of fins of a cross fin tube after expansion, wherein FIG. 2A shows a case where a fin pitch is normal, and FIG. It represents what is.

[Explanation of symbols]

 2 Aluminum plate fin 4 Collar part 6 Assembly hole 8 Heat transfer tube 10 Curl part 12 Expander

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiro Seiya 5-3-1-3 Shimbashi, Minato-ku, Tokyo Inside Sumitomo Light Metal Industries Co., Ltd. (72) Inventor Mitsuhiro Tamaki 5-1-1-3, Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd. (72) Inventor Shinbi Harada 5-1-1-3 Shimbashi, Minato-ku, Tokyo Sumitomo Light Metal Industry Co., Ltd. (72) Inventor Kido Open 5-1-1, Shimbashi, Minato-ku, Tokyo No. Sumitomo Light Metal Industries Co., Ltd. (56) References JP-A-7-43092 (JP, A) JP-A-6-39347 (JP, A) JP-A-6-41573 (JP, A) JP-A-3 -252461 (JP, A) JP-A-7-43093 (JP, A) JP-A-5-311123 (JP, A) JP-A-7-43091 (JP, A) JP-A-61-227877 (JP, A) ) JP-A-53-125437 (JP, A) 73934 (JP, B2) JP-B-57-46000 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F28F 1/32 F28F 13/18

Claims (2)

(57) [Claims] 1. A While assembly bore formed by providing a cylindrical collar portion of the predetermined height in the hole around the Ru formed a plurality, of the collar portion
The curled part is in a state where the tip warps its inner surface.
Using aluminum plate fins
One or more of the minium plate fins
Contact each other so that they match,
Insert the heat transfer tube through the matching mounting hole
Then, by inserting an expander into the heat transfer tube,
Expand the heat transfer tube, and
The heat transfer tube and aluminum plate
Cross fin integrated with rate fin
In manufacturing the tube, a hydrophilic film is formed by a hydrophilic surface treatment over the entire surface, and a water-soluble film is formed on the hydrophilic film .
Polyether and / or its esterified or higher
A layer formed by applying a water-soluble lubricant comprising an alkali metal salt of a fatty acid is further formed on the aluminum plate.
Using aluminum fins, press-forming the aluminum
Fins and heat transfer tubes
By assembling, the expansion by inserting the expander is performed.
Suppress or prevent fin pitch disturbance caused by pipe
Cross fin chute characterized by stopping
How to make 2. The amount of the lubricant applied to the aluminum plate fin material is 0.05 to 0.5 g / m ^2.
The cross fin tube according to claim 1, wherein
Production method .