JPH0612219B2 - Heat exchanger manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a heat exchanger, and more specifically, as a condenser, an evaporator, an oil cooler or a radiator in an industrial machine or an air conditioner for an automobile. It relates to a suitable method for manufacturing a heat exchanger whose material is aluminum.

[Prior Art] Conventionally, heat exchangers A1 to A5 as shown in FIGS. 4 to 8 have been used as condensers, evaporators, oil coolers or radiators in industrial machines and air conditioners for automobiles. Of these, the heat exchanger A shown in FIG.
Reference numeral 1 denotes a condenser, which connects a refrigerant inlet 1a and an outlet 1b to a tube body B1 bent in a meandering shape, and further combines a heat-dissipating corrugated fin C1 formed from a brazing sheet in a heating furnace. It was brazed and integrated. One or a plurality of refrigerant passages 4b are formed in the tube body B1 as shown in the cross section of FIG. The brazing sheet has a thickness of 0.1.
It is an aluminum alloy-based plate material of about 6 to 0.20 mm, and has a lower melting point than that on the surface of the core alloy, for example, A
It is a coating of 1-Si based braze alloy. Then, brazing is performed by melting the brazing alloy on the surface of the brazing sheet in a heating furnace.

Further, the heat exchanger A2 in FIG. 5 is an evaporator, which is similar to the above-mentioned condenser in that the tube body B2 and the corrugated fin C2 are joined together, and the refrigerant body inlet 2a and outlet 2b are connected to the tube body B2. It is a thing. The heat exchanger A3 shown in FIG. 6 is also an evaporator, which is formed by stacking core plates B3 having cavities through which the refrigerant passes, joining corrugated fins C3, and further introducing an inlet 3a and an outlet of the refrigerant to the core plate B3. 3b is connected. The heat exchanger A4 in FIG. 7 is an oil cooler, which uses a straight pipe B4 instead of the meanderingly bent pipe body B1, and has a corrugated fin C4 and a liquid chamber D in the straight pipe.
4 is joined, and the refrigerant inlet 4a and outlet 4b are connected to the liquid chamber D4. The heat exchanger A5 shown in FIG.
It is a radiator, which, like the oil cooler above,
The straight pipe B5, the corrugated fin C5, and the liquid chamber D5 are joined, and the inlet 5a and the outlet 5b of the cooling water are further connected.

That is, the manufacturing method of these heat exchangers A1 to A5 is
As described above, a brazing sheet is used as a material for the corrugated fins C1 to C5, and after each member is assembled, the brazing sheet is placed in a heating furnace and heated to melt the coating alloy on the surface of the brazing sheet so that other members can be melted. It was something that was brazed with and integrated.

The paint was sprayed onto the integrated heat exchangers A1 to A5 and dried to complete the process.

[Problems to be Solved by the Invention] However, in the production of the heat exchangers A1 to A5, thin brazing sheets as corrugated fins C1, C2, and C3 are provided for the purpose of reducing weight and reducing material and production costs. When, for example, as shown in the enlarged sectional view of FIG. 10, a fillet E6 is formed and the corrugated fin C6 is brazed to the tubular body B6,
There is a fatal defect that the core alloy is corroded by the Al-Si brazing alloy coated on the surface of the brazing sheet, and the corrugated fin C6 buckles as shown in the figure. That is, attempts to reduce the thickness of the brazing sheet as the material of the corrugated fin C6 were naturally limited. Further, in the method using the brazing sheet, there is a problem that a process of coating by spraying after brazing and integration is required for coating the surface, which complicates the working process.

[Means for Solving the Problems] The present invention replaces a method of combining a corrugated fin and a tube body having a refrigerant passage or a core plate having a cavity serving as a refrigerant passage, and brazing the two together. The problem is solved by using a thermosetting adhesive containing a pigment for integration.

That is, the present invention comprises, in manufacturing a heat exchanger, a core plate having a tubular body having a refrigerant passage or a cavity serving as a refrigerant passage, and a corrugated fin provided on the surface of the tubular body or the core plate. The step of solvent degreasing the heat exchanger core before or after assembling, the entire assembled heat exchanger core by the spray method, pigment: solvent: adhesive = 2-10%: 60-90 %:
After applying a low-viscosity liquid adhesive consisting of 5 to 30%, high pressure air is blown to remove excess adhesive, and the heat exchanger core formed in the above step is placed in a curing oven to remove The gist is a method for manufacturing a heat exchanger, which comprises the steps of curing an adhesive and baking a pigment.

Here, the adhesive composition is pigment: solvent: adhesive = 2 to 10
%: 60 to 90%: When it is in the range of 5 to 30%, good adhesion can be achieved and an excellent coating film can be formed. Further, it is desirable that the thickness of the applied adhesive is 5 to 40 μm. If the thickness is in this range, it does not impair the heat exchange performance,
In addition, a pigment layer that sufficiently protects the surface of the heat exchanger can be formed by baking.

A meandering bent pipe or a straight pipe is used as the pipe body, and a union, a pipe, or the like is used as a connecting member attached to the entrance of the pipe body or the core plate. Aluminum or an alloy thereof can be applied to the material of the above-mentioned tubular body, core plate or corrugated fin.

Further, the adhesive is made of Al having a particle size of 20 to 200 μm.
-Zn-based alloy, Cu, Ag or powder of the alloy is used for 3
It is desirable to contain -60%. This is because the above-mentioned powder and granules make the adhesion stronger and provide a cathodic corrosion protection effect at the bonded portion, and further, the contact heat resistance between the tube body or core plate and the corrugated fin is significantly reduced, resulting in good heat resistance. This is because it gives conductivity.

In addition, as the adhesive, for example, an epoxy-based nylon-modified epoxy-based, nylon-based, nylon-epoxy-based, acrylic-based, nitrile-rubber-based, acryl-epoxy-based, etc. thermosetting adhesive is used. You can

The material of the corrugated fin is Al-Mn.
-Cu system, Al-Mn-Zn system, Al-Mn-Zn-S
n-based, Al-Mn-Zn-Cr-Zr-based, Al-Mn-
An Sn-based, Al-Mn-Zn-In-based, Al-Mg-based alloy, or the like can be applied.

[Operation] In the first step in the method for manufacturing the heat exchanger of the present invention,
A core plate having a tubular body having a refrigerant passage or a cavity serving as a refrigerant passage, and a corrugated fin provided on the surface of these tubular bodies or core plates, and a heat exchanger core, before assembling the parts thereof, Alternatively, since the solvent degreasing is performed after the assembly, it has an action of removing the processing oil attached at the time of processing the parts, and has an action of increasing the adhesive strength by the adhesive described later.

In the next step, since the low-viscosity liquid adhesive containing the pigment in a predetermined ratio is applied to the entire assembled heat exchanger core by the spray method, the adhesive can be easily applied. Then, after applying the adhesive, high-pressure air is blown, so that the excess adhesive that has adhered can be easily removed, and clogging of the corrugated fins and excessive adhesion of the corrugated fins can be prevented. This has the effect of preventing the performance of the heat exchanger from deteriorating.

In the next step, the heat exchanger core is put in a curing oven and heated to cure the adhesive to bond the members of the heat exchanger to each other and simultaneously bake the pigment.

By performing the above steps, the adhesive is hardened and the pigment is baked at the same time, so the steps of spraying and drying the paint can be omitted, and the heat exchanger can be manufactured very easily.

Moreover, since the heat exchanger can be manufactured without using a brazing sheet as a material for the corrugated fins, the corrugated fins can be made extremely thin.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing a manufacturing process of a heat exchanger (condenser) by the method of the present invention.

(A) Part manufacturing process First, a flat tube body 4 provided with a plurality (or one) of refrigerant passages 2 is bent by a known forming means to be formed in a meandering shape. The material of the tube body 4 is pure aluminum,
An Al-Mn-based alloy, an Al-Mn-Cu-based alloy, an Al-Cu-based alloy, or the like is used. Next, the corrugated fins 8 bent into a corrugated shape are formed from the coil material unwound from the original coil 6 of the thin aluminum sheet by known roll forming or press forming means. Examples of the thin aluminum sheet include an aluminum alloy bare material having a thickness of 0.03 to 0.13 mm.

(B) Assembly Step Next, the tube body 4 and the corrugated fins 8 are set in the shape of the heat exchanger core 14 by the assembly jig 12.

(C) Degreasing process Next, the solvent degreasing process of the assembled heat exchanger core 14 is performed. This solvent degreasing treatment is intended to remove the processing oil that has adhered during the processing of the parts, and thereby further enhances the adhesive strength of the adhesive described later. The solvent degreasing treatment liquid L used in this treatment is a treatment liquid generally used industrially, for example, 1.
1.1-Trichloroethane, trichloroethylene, perchlorethylene, trichlorotrifluoroethane, etc. are used. As a degreasing method, vapor degreasing is used in which the heat exchanger core 14 is placed on the shelf 16 having the through holes 16a provided in the steam tank 15, the degreasing solution is heated, and the steam is degreased. However, as another method, hot liquid immersion may be performed in which the liquid is directly immersed in the treatment liquid.

(D) Adhesive Applying Step Next, a low-viscosity adhesive containing a black pigment diluted with a solvent is uniformly applied to the entire heat exchanger core 14 degreased with the solvent by a high pressure spray method. Carbon black is used as the pigment, and diacetone alcohol is used as the solvent for the pigment. And as the component ratio of the above-mentioned pigment, solvent and adhesive, it is respectively in the range of 2 to 10%, 60 to 90% and 5 to 30%, preferably 3 to 5%, 80 to 85% and 10 to 15%, respectively. It is suitable if it is within the range. The thickness of the applied adhesive is 5
It is 40 microns, preferably 15-30 microns.

And then, compressed air is blown to remove excess adhesive.

Examples of the type of the adhesive include thermosetting adhesives such as epoxy type, nylon-modified epoxy type, nylon type, nylon-epoxy type, acrylic type, nitrile-rubber type, and acrylic-epoxy type. . In this adhesive, an Al-Zn alloy (for example, American Aluminum Association standard AA7072 alloy) or Cu, Ag is used.
By containing the granular material made of the alloy and its alloy, the adhesive strength is increased, and the cathodic protection effect in the adhesive portion 19 is obtained, and further, the contact thermal resistance between the tubular body 4 and the corrugated fin 8 is significantly reduced, Good thermal conductivity is obtained. In particular, the particle size of the granules is 20-200 microns,
Preferably 3 to 60% of 50 to 100 microns,
When the content is preferably 10 to 50%, a heat exchanger excellent in both the adhesive strength, the cathodic protection effect and the thermal conductivity can be obtained.

(E) Connecting Member Connecting Step Next, as a connecting member with another member, the union 20 is fitted into the tube body 4, and the adhesive in the syringe 22 is injected into the joint portion 24. As a method of attaching the union 20, the tube body 4 may be molded and subsequently joined by argon welding, torch brazing, or an adhesive.

(F) Heating Step Next, the heat exchanger core 14 thus formed is placed on the tray 26 and placed on the belt conveyor 30 running in the curing furnace 28, depending on the type of adhesive used. 80 ~
The adhesive is hardened by heating in a temperature atmosphere of 200 ° C., and the tubular body 4, the corrugated fins 8 and the tubular body 4 are formed.
And the union 20 are integrated. At this time, since the black pigment contained in the adhesive is baked, there is no need for subsequent coating and drying steps, the number of steps is small, and the manufacturing cost can be greatly reduced.

As the shape of the corrugated fins 8, for example, various types that can be normally formed are applied as shown in a partially enlarged view of FIG. Among these, as shown in FIG. 2 (a), for example, there is one in which the adhesive portion between the U-shaped corrugated fin 8a and the tubular body 4a is surrounded by a fillet 34a.
As shown in FIG. 2 (b), a U-shaped corrugated fin 8
The apex of b is made flat, the flat surface 8bb and the tube body 4b are brought into close contact with each other, and the bonded portion is surrounded by the fillet 34b, or as shown in FIG. 2 (c), the corrugated fin 8c.
It is preferable that the flat surface 8cc and the tube body 4c are in close contact with each other and the bent portion is surrounded by the fillet 34c from the viewpoint of ensuring the adhesive strength and also from the viewpoint of heat exchange performance.

FIG. 3 is an explanatory view showing an embodiment of a manufacturing process of a laminated type heat exchanger according to the method of the present invention.

(A) Component manufacturing process First, the core plate 4 provided with the hollow coil 42 serving as a refrigerant passage and the upper and lower communication ports 44a and 44b from the original coil 40 of a slightly thick aluminum sheet of 0.3 to 1.0 mm.
6, the end plate 48 having the refrigerant inlet port 48a and the refrigerant outlet port 48b is formed by a known method (press working). Further, the corrugated fin 50 is formed in the same manner as in the first embodiment.

(B) Degreasing step Next, each molded member is placed in the liquid tank 52 containing the same degreasing agent as in the first embodiment, and hot liquid degreasing is performed.

(C) Adhesive Applying Step Next, after applying an adhesive to the surfaces of the core plate 46 and the end plate 48 in contact with each other, the assembly jig 54 is used to
Corrugated fin 50, core plate 46 and end plate 48
Assemble. Thereafter, as in the case of the first embodiment, after the adhesive containing the black pigment is sprayed by the spray method, high pressure air is sprayed to remove the excess adhesive.

(D) Connecting Member Connecting Step Next, the connecting member 60 such as a pipe is fitted and the adhesive is injected into the fitting portion 61.

(E) Heating Step Next, the heat exchanger core 56 is put into the curing furnace 62 to cure the adhesive and bake the pigment to complete the heat exchanger. Next, an experimental example of the heat exchanger (vehicle condenser) of the first embodiment will be described.

(Experimental example) In the experiment, the heat exchanger was manufactured by changing the ratio of the pigment, the solvent, and the adhesive, and the adhesion state and the coloring state at that time were investigated. The experimental conditions are shown in Table 1 below, and the results are shown in Table 2 below.

As described above, in the case of this example, a good black baking coating was obtained by using the adhesive containing the pigment in the predetermined range. On the other hand, the comparative example has a problem that a coating film cannot be formed or a suitable coating film cannot be obtained.

By manufacturing the heat exchanger as shown in the first and second embodiments, the following effects can be obtained.

Since the adhesive can be hardened and the heat exchanger cores 14 and 56 can be joined together and the pigment can be baked at the same time, the steps of spray painting and drying as separate steps can be omitted, and the work steps can be reduced. You can As a result, the manufacturing cost can be significantly reduced.

Since the adhesive is applied by the spray method, the adhesive can be uniformly processed in a short time, whereby the manufacturing cost can be reduced.

By blowing high-pressure air after applying the adhesive, it is possible to easily remove the excess adhesive, thereby preventing the corrugated fins 8 and 50 from being clogged, so that the heat exchange performance can be prevented from being degraded. .

Since the joining members 20 and 60 such as unions can be joined at the same time in the curing furnaces 28 and 62 when joining the tube body 4 or the core plate 46 and the corrugated fins 8 and 50, manufacturing is facilitated.

As a material for the corrugated fins 8 and 50, a non-blazing sheet can be applied.
0 is not eroded by the braze alloy, so
Even if the corrugated fins 8 and 50 are made very thin, buckling of the corrugated fins does not occur, so that the weight of the heat exchanger can be reduced.

Further, as the material for the corrugated fins 8 and 50, Al- which has not been used conventionally for corrosion by a brazing alloy is used.
Mn-Cu system, Al-Mn-Zn system, Al-Mn-Zn
-Sn system, Al-Mn-Zn-Cr-Zr system, Al-M
n-Sn system, Al-Mn-Zn-In system or Al-Mg
It is possible to use a thin-walled coil having high strength and high corrosion resistance, such as a series alloy, and by using these, weight reduction and material cost reduction can be realized.

Compared with brazing in which high temperature heating (600 ° C.) is performed, low temperature heating (80 to 200 ° C.) for a short period of time is sufficient, which requires less electric power and can significantly reduce manufacturing cost.

The aluminum material used, including the corrugated fins 8 and 50, is the softening temperature of aluminum (usually 360 ° C).
Since the following treatment can be performed, the initial work hardening strength can be maintained, and therefore the rigidity and strength of the product are high.

Since the manufacturing equipment is simple and no special technology is required, manufacturing is easy.

It is not necessary to use an expensive material such as the brazing sheets 8 and 50, and the material cost can be reduced.

[Advantages of the Invention] As described above, according to the present invention, since the adhesive containing the pigment in the above-described range is used, the steps of painting and drying can be omitted, and the number of manufacturing steps can be reduced. Has a great effect. Further, since the adhesive is applied by the spray method, it can be uniformly processed in a short time. Thereby, the manufacturing cost can be significantly reduced. Also, since the corrugated fin can be made extremely thin,
It is possible to reduce the weight of the heat exchanger. Further, as compared with brazing which is heated at a high temperature, curing of the adhesive can be performed at a low temperature for a short time, which has the advantage that the rigidity and strength of the product are increased, and it is not necessary to raise the temperature so much. It requires less power and can significantly reduce manufacturing costs. Moreover, since it is not necessary to use an expensive material such as a brazing sheet, the material cost can be reduced, and the manufacturing facility and technology are also easy to manufacture.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a manufacturing process of the heat exchanger of this embodiment,
FIG. 2 is a sectional view showing a joined state of a tubular body and a corrugated fin, FIG. 3 is an explanatory view showing a manufacturing process of a heat exchanger using a core plate, and FIGS. 4 to 8 are explanatory views of a conventional example. ,
FIG. 9 is a sectional view of the tubular body, and FIG. 10 is an explanatory view showing the problems of the conventional example. 4 ... Tube 8,50 ... Corrugated fin 14,56 ... Heat exchanger core 20 ... Union 28,62 ... Curing furnace 46 ... Core plate

Claims (1)

[Claims] 1. In manufacturing a heat exchanger, a core plate having a pipe body having a refrigerant passage or a cavity serving as a refrigerant passage, and a corrugated fin provided on a surface of the pipe body or the core plate are provided. A step of solvent degreasing the heat exchanger core before or after assembling, by a spray method on the entire assembled heat exchanger core, pigment: solvent: adhesive = 2 to 10%: 60 to 90% :
After applying a low-viscosity liquid adhesive consisting of 5 to 30%, high pressure air is blown to remove excess adhesive, and the heat exchanger core formed in the above step is placed in a curing oven to remove A method of manufacturing a heat exchanger, which comprises the steps of curing an adhesive and baking a pigment.