JPS59142392A - Heat exchanger - Google Patents

Abstract

PURPOSE:To provide a heat exchanger having especially good heat resistance and cooling liquid resistance, which is quite suitable to a radiator for a car, by applying a water-tight fixing method to the fitting part of a heat exchanger, using additive type liquid silicon rubber as an adhesive sealing agent, as a substitute for the conventional rubber packing. CONSTITUTION:When a heat exchanger is assembled, the fitting part 10 at the edge of a tank 2 is fitted into the groove 20 of a core plate 16. At that time, the inside and the outside walls 13 and 14 of a fitting part 10 are respectively fitted into the inside and the outside walls 17 and 18 of a groove 20, respectively. The gap between the lower acting surface 11 at the bottom of a fitting part 10 and the inner surface of the bottom wall 19 of a groove is filled with a silicon rubber adhesive sealing agent 26. A claw 22 is tightened toward the acting surface 12 on the outside of a fitting part 10 at the edge of a tank 2. An additive type liquid silicon rubber adhesive sealing agent is used for the above-mentioned adhesive sealing agent 26. By using the rubber adhesive sealing agent, the difference caused by relative displacement between a tank made of synthetic resin and a core plate can be well absorbed, in comparison with a case that a conventional heat-hardening type epoxy resin adhesive agent is used, so that internal stress generated on the adhesive surface can be alleviated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a heat exchanger in which a core plate 1 is attached to a synthetic resin tank by tightening, and is suitable for use in, for example, an automobile radiator.

In the conventional heat exchanger, as shown in FIG. 1, a core plate 16 is provided on the end face of the core part, the outer peripheral edge of the core plate 16 is formed into a groove shape, and a synthetic resin tank 2 is placed in the groove 20. Fitting the mounting portion 10 with a substantially square cross section provided on the edge,
Furthermore, by tightening the constriction plate 22 from the outer surface of the groove-shaped portion 20 of the core play 16 to 10 degrees at this mounting portion,
It is designed to be sealed and attached to the tank 2 core plate 16. Then, the tank edge attachment part 1 fitted into the groove 20
A rubber gasket 21 is installed between the bottom surface 11 of the groove 0 and the groove bottom surface 19 to maintain a seal.

However, watertight fixation using such a rubber pankin 21 was not particularly satisfactory in terms of heat aging resistance and cooling liquid resistance. In other words, if you attach it to your car and drive for a long time,
It is affected by the high temperature inside the engine room, or by amines, ammonia, etc. mixed in the engine coolant. Here, the former causes cranking or permanent deformation in the rubber packing 21, while the latter causes chemical behavior called corrosion and stress at the contact surface between the core plate 16 and the rubber packing 21, for example. Stress corrosion cracking occurs due to the synergistic effect of physical behavior. Of course, in either case, engine coolant often leaks and causes overheating.

On the other hand, conventional methods have been proposed for fixing the tank and core plate in a watertight manner using heat-curable epoxy resin adhesives, thermosetting or thermoplastic resin powders (especially polyamide-based, epoxy-based, and polyimide-based powders). There is. However, these adhesives have low impact resistance, and therefore, when actually used, they have the serious drawback of prematurely peeling off at the adhesive interface with the synthetic resin tank, resulting in significantly poor long-term durability. Ta.

In view of the above problems, the present invention provides a heat exchanger with particularly excellent heat resistance and coolant resistance by using an additive-type liquid silicone rubber adhesive sealant instead of a rubber pankin to perform watertight fixation. The purpose is to provide equipment.

According to the present invention, after cleaning the joint surface of the heat exchanger, the above-mentioned additive liquid silicone rubber adhesive sealant is applied, and then cured under predetermined curing conditions to form an adhesive layer. A heat exchanger with excellent durability and watertight fixing power can be obtained. According to the present invention, the adhesive layer of the heat exchanger, that is, the watertight fixing portion, has particularly excellent resistance to heat aging and resistance to coolant. Therefore, even after being installed in a car and driven for a long time, it has a strong water retention force, which extends the life of the heat exchanger, which has the great advantage of stabilizing quality and reducing costs.

In addition, since the present invention uses a rubber-based adhesive sealant, the difference in relative displacement due to thermal expansion between the synthetic resin tank and the core plate is greater than that of conventionally proposed heat-curing epoxy resin adhesives. can be absorbed well, and the internal stress generated at the adhesive interface can be alleviated. Therefore, the heat exchanger of the present invention has excellent impact resistance.

Hereinafter, the present invention will be explained in more detail based on embodiments shown in the drawings.

This embodiment is applied to a heat exchanger as a radiator for an automobile, and FIG. 2 shows the entire radiator for an automobile. The radiator includes a metal core part 1 including corrugated fins 7 made of copper and tubes 8 made of brass layers, and tanks 2 and 3 made of synthetic resin sealed at the upper and lower ends thereof.

The upper tank 2 is equipped with a cooling water inlet 4 and a cooling water inlet pipe 5, and the lower tank 3 is equipped with a cooling water outflow vibro, but basically the upper and lower Although the tanks have the same structure, only the upper tank 2 will be explained below.

FIG. 3 shows a structure in which the tank 2 is hermetically attached to the core part 1. As shown in the figure, the tank 2 is open at one end, and by covering it over the core plate 16 at the end of the core part 1. Tank 2 is now complete. Therefore, tank 2
A mounting portion 1o having a substantially rectangular cross section is provided along the entire circumference of the open end. This mounting part 1o has upper and lower active surfaces 11.12 with mutually parallel flat surfaces and inner and outer side wall surfaces 13.1'4 at right angles to these.

A core plate 16 made of a brass layer with a plate thickness of about 0.5 m+n is fixed to the end of the core part 1, specifically the tube 8, near its upper and lower ends by appropriate means, such as soldering or brazing. It is. The outer peripheral edge of the core plate 16 is the inner and outer side walls 1
7.18 and a groove 20 having a bottom wall 19.

Then, during assembly, the edge attachment part 10 of the tank 2 is fitted into the groove part 20, and at this time, the inner and outer side wall surfaces 13 and 14 of the attachment part 10 are replaced by the inner and outer side walls 17 of the groove part 20, respectively.
．． 18. Further, the lower working surface 11 of the mounting portion 10
A silicone rubber adhesive sealant 265 is filled between the groove portion bottom wall 19 and the inner surface thereof. In one example, a constriction plate 23 made of an iron plate having an approximately L-shaped cross section (inverted in the figure, but L-shaped on the opposite side) with a claw portion 22 at the top edge is attached to the core plate. 16 to tighten the pawl 22 toward the outward working surface 12 of the edge attachment portion 10 of the tank 2. As a result, the tank edge attachment portion 10 is securely and hermetically attached to the groove portion 20 of the core plate 16 by both the adhesive force of the adhesive sealant 26 and the holding force of the constriction plate 23.

That is, in this example, an additive-type liquid silicone rubber adhesive sealant is used instead of the conventional rubber gasket 21, and instead of sealing by surface pressure like the rubber gasket (0 ring), it is sealed by adhesive. That's what I'm doing.

As shown in Fig. 3, the constriction plate 23 may be installed in order to further improve the seal durability, but it should not be installed (this heat exchanger performs a sufficiently excellent function). .

Next, the adhesive sealant 26 will be explained in detail.

This adhesive sealant 26 uses an addition-type liquid silicone rubber adhesive sealant, and its composition and formulation include a curing catalyst such as a platinum compound, perilla as a filler, and Venkara as other additives. A mixture of 100 parts by weight of a dimethylpolysiloxane base polymer and 100 parts by weight of a crosslinking agent, which is a silane compound having a polyfunctional group, was sufficiently kneaded and slightly conditioned.

The biggest feature of this addition-type liquid silicone rubber adhesive sealant 26 is that although the base polymer itself is a low modulus squib with elongation of 400% or more, it has a low swelling rate with cooling fluids and has high resistance to cooling fluids. That's excellent. Lowering the modulus of the adhesive sealant improves its ability to follow dimensional changes due to heat and cooling fluid in the synthetic resin tank, and also makes it easier to adjust the relative displacement difference between the metal and the synthetic resin. This is to improve the seal durability by absorbing it in the adhesive sealant and by the absolute amount of elongation of the adhesive sealant.

Here, it is generally believed that lowering the modulus reduces the amount of filler, which leads to a decrease in coolant resistance. Therefore, in consideration of this point, the adhesive sealant 26 of this example improves resistance to cooling fluids by improving the shape of the crosslinking agent (including the shape of the functional group) and increasing the crosslinking density.

Furthermore, a substance that selectively captures alkaline substances (especially amines) contained in coolants, etc. is introduced into the silica (filler), and the silica surface is also treated with silane to improve resistance to coolants. I let it happen. On the other hand, in order to particularly improve adhesion with synthetic resins, an adhesion promoter was introduced into the base polymer to increase the hydrogen bond density.

Next, the outline of the manufacturing process of the heat exchanger will be explained.

First, the grooves 20 of the core plays 1 and 16 and the joint surface 11 of the resin tank attachment part 10 are cleaned to remove impurities such as dust and oil. After washing with water, the core plate 16 is drained and dried, and an additive liquid silicone rubber adhesive sealant is applied to the grooves of the core plate 16. After application, the adhesive sealant is cured under predetermined curing conditions (if a tightening process is necessary to properly bond the degreased resin tank 2, it is tightened before the adhesive sealant hardens), and the adhesive sealant is cured under predetermined curing conditions to be completely watertightly fixed.

Next, a specific manufacturing method will be explained in more detail. First, the core plate 16 is cleaned with an alkaline cleaner containing sodium silicate as the main component (manufactured by Yuken Kagaku 0 Kiku; Pakuna 2.00TA).
was immersed in an alkaline cleaning bath adjusted with tap water to a concentration of 20 g/β for 3 minutes at a temperature of 60°C to perform degreasing and cleaning. Next, in order to wash off the alkaline cleaning solution adhering to the adherend, the adherend is thoroughly washed in running water at room temperature, and then dried in a hot air circulation type drying oven at a temperature of 120° C. for 20 minutes to remove the moisture. After draining and drying in this way,
Apply an additive liquid silicone rubber adhesive to the core plate 16.
An automatic coating device is used to coat the groove portion 20 with a uniform film thickness (appropriate film thickness is about 500 μm). in this case,
It is preferable for the adhesive sealant to have excellent flow properties to the extent that it does not drip from the application nozzle in terms of ease of application, but the adhesive sealant of this example has moderately excellent flow properties.

Further, the joint surface 11 of the resin tank 2 is wiped with trichlene or acetone to remove impurities and degrease.

Thereafter, the resin tank 2 is joined to the core plate 16, and if a tightening process is necessary, the tightening process is completed before the adhesive is cured. Furthermore, in order to harden the adhesive sealant 26, it was placed in a hot air circulation drying oven again for 30 minutes at a temperature of 150°C.
Heating is performed for a minute to form an adhesive sealant layer 26 as shown in the figure.

In addition, the material of core play) 16 used in this example is:
Brass C2600-P, resin tank made of nylon 66 with 30% glass fiber as an auxiliary material.

The following experiment was conducted using the heat exchanger manufactured in this manner. The experimental capacity and experimental results will be explained below.

Example Using the above-mentioned additive liquid silicone rubber adhesive sealant 26, an experiment was conducted to see how the cooling liquid resistance (adhesive sealability) of the fixing part of a heat exchanger differs depending on the introduction of an adhesion promoter. For evaluation, engine cooling water (product name Toyota Genuine Castle Long Life Coolant) diluted to 50% with tap water was sealed inside the heat exchanger shown in Figure 1 as a coolant and circulated inside to prevent leakage. This is the durability time until the end. The cooling liquid circulation conditions are 8 hours/day; circulation (temperature 80°C, flow rate approximately 1.5 m/s'ec)
, 16 hours/day; circulation stoppage is repeated, and the above durability time is the cumulative time.

(Hereinafter in the margin) Table 1 (Hereinafter in the margin) The results are shown in Table 1. As can be seen from the first surface strength (1), it can be seen that the polymer in which the adhesion promoter is introduced has excellent water honey fixing power (seal chipping resistance).

EXAMPLE An experiment was conducted to determine how the cooling resistance of the fixed part of the heat exchanger differs depending on the surface treatment of the filler (silica), etc. in the above-mentioned additive-type adhesive silicone comb type adhesive sealer 26. Note that n-plane (as a plane, Experimental Example 1
is the same as

(Left below) Table 2 The results are shown in Table 2. As is clear from this second table,
It can be seen that the filler (silica), in which the surface of fumed silica is treated with silane and an amine-capturing substance is added, has excellent water nectar fixing power (seal durability).

Example 6 An experiment was conducted to examine how the adhesive sealing properties of the fixing part of a heat exchanger differ depending on the modulus of the rubber after curing in the addition-type liquid silicone rubber adhesive sealant 26.As an evaluation, the following is an experimental example. Same as 1.

(Left below) Table 3 The results are shown in Table 3. As is clear from this Table 3,
Adhesive 26 with low modulus (high elongation rate)
It can be seen that it has excellent watertight adhesion (seal durability).

Examples Conventional rubber packing (E) of adhesive sealant according to the present invention
PDM) and other resin-based adhesive sealants were used, and the heat exchanger aging resistance and coolant resistance of these heat exchangers were compared.

As an evaluation, the aging resistance of the heat exchanger was determined by leaving the heat exchanger in a 130"C atmosphere and then checking for leakage by measuring the pressure at 1.8 kg/ca. Note that the cooling liquid resistance was the same as in Experimental Example 1. be.

The composition of the adhesive sealant is as follows.

Condensation type "RTV liquid silicone rubber thread - Toshi Silicone @ product name 5E5012 Acrylic resin system □ Electrochemical (Kiyoshi product name Hardlock M600 Chlorosulfonated polyethylene system □ Threepond product name TB1' 104 Epoxy Resin system - 100 parts by weight of epoxy resin (Epicote 828 manufactured by Nigel Kagaku 01), dicyandiamide 7
parts by weight, 70 parts by weight of sodium silicate, 10 parts by weight of NBR (having a reactive group at the end), and 1 part by weight of a silane coupling agent.

(Left below) The results are shown in Table 4. As is clear from this Table 4,
Heat exchangers using additive-type liquid silico rubber-based adhesive sealants have much better effects than those using conventional rubber seals (O-rings) and other adhesive sealants.

From the above results, it is clear that the watertight fixing power of the additive liquid silicone rubber adhesive sealant explained in this example is better than that of the conventional method using a rubber pankin (0 ring) or other resin adhesive sealant. Compared to conventional heat exchangers, this heat exchanger has excellent aging resistance and coolant resistance, so it can be used for long periods of time without causing coolant leakage.

Furthermore, the automotive resin tank copper radiator of this example was subjected to other durability tests, such as a thermal cycle test (130'
c, = -30°C), etc., it showed durable watertight fixing power for more than 13,000 hours, and it was confirmed that it could sufficiently withstand long-term use.

Although the above embodiment shows an example in which the core plate 16 and the resin tank mounting portion 10 are fixed with an adhesive sealant having the composition described above, the present invention also includes the shape effect of the seal portion to improve seal durability. and activation of the interface of the adherend (surface treatment such as coating with brimer).

Next, an example regarding the shape effect of the seal portion will be described.

Embodiment concerning the shape effect of the seal part> The embodiment shown in FIG.
The adhesive sealant 26 was simply applied to the area where the ring) intervened (see Figure 1), but in order to make the adhesive more effective, it was necessary to attach the core plate 16 and the tank. The shape of the portion 10 may be changed.

In the embodiment shown in FIG. 4, a chamfer is provided on the adhesive portion 11 of the resin tank 2 in order to increase the adhesive area of the adhesive sealant 26. In the case of this shape as well, the constriction plate 22 is not necessarily required.

In the example shown in FIG. 5, in order to further increase the bonding area of the adhesive sealant 26, the mounting portion 10 of the resin tank 2 has a circular cross-sectional shape, and the core plate 16 also has a circular cross-sectional shape. . As a result, the mounting portion 10 is bonded over almost the entire circumference.

Further, in the example shown in FIG. 6, the cross-sectional shape of the resin tank mounting portion 10 is polygonal, and the cross-sectional shape of the core plate 16 is
The shape includes a groove portion 20, a resin tank holding portion 27, and a guide portion 28 for inserting the resin tank.

When using an additive liquid silicone rubber adhesive sealant, the shapes shown in FIGS. 4 to 6 are very effective. In particular, the shape shown in FIG.
In addition to increasing the adhesive area of 6, the core play F1
Since the resin tank holding portion 27 is formed at 6, the sealing effect is further improved. Further, the resin tank 2 can be easily assembled by having the guide portion 28. That is, the outer wall surface 14 of the tank mounting portion 10 is brought into contact with the guide portion 28, and in this state, the mounting portion 10 is inserted into the groove 2.
When the core plate 16 is pressed into the groove 20, the core plate 16 is expanded by its own elasticity, and the mounting portion 10 is properly fitted into the groove 20. As a result, work efficiency is improved, which has the great advantage of significantly reducing costs.

The assembly process for the heat exchanger having the seal portion shape of the embodiment shown in FIGS. 4 to 6 is the same as that of the embodiment shown in FIG. 4 described above.

Next, an example regarding activation of the adherend interface will be described.

Example regarding activation of adherend interface As shown in FIG.
In order to improve the adhesion with the moldable liquid silicone adhesive sealant 26, it is effective to apply a primer 29 containing a silane compound, for example, a primer 29 (dissolved in the solvent toluene). .

The coating method in this case is that after removing impurities from the resin tank joint surface 11, a brimer 29 containing a silane compound is applied.
One layer of primer 29 is formed by heating in a hot air circulation drying oven at a temperature of 60° C. for 15 minutes.

Note that the formation of the primer layer 29 is not limited to the resin tank 2, but is equally effective even when it is formed on the metal bonding surface of the core plate 16 or the like.

In addition to the embodiments described above, the material of each component of the heat exchanger may be other than copper, such as steel or aluminum, and the tank 2 may be made of metal, or may be made of a combination of the above materials. There is no problem in configuring the parts.

Furthermore, it goes without saying that the heat exchanger of the present invention can be applied not only to the heat exchanger for automobiles but also to heat exchangers for air conditioning such as heater cores of hot water type heating systems for automobiles.

As detailed above, in the heat exchanger of the present invention, an additive-type liquid silicone adhesive sealant is used as an alternative to the rubber packing (O-ring), so it is possible to reliably seal between the core plate and the tank. As a result, a high-quality heat exchanger with no stress corrosion cracking of the core play 1 and excellent heat aging resistance can be obtained.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the tank mounting part of a conventional heat exchanger.
Fig. 2 is a front view showing one embodiment of the heat exchanger of the present invention;
The figure is a sectional view taken along the line mm in FIG. 2, and FIGS. 4 to 7 are sectional views showing essential parts of other embodiments of the heat exchanger of the present invention. 2... Tank, 8... Tube, 16... Core plate, 26... Adhesive sealant N (additional liquid silicone rubber type), 27... Primer agent layer. Representative Patent Attorney Takashi Okabe Procedural Amendment Letter March 23, 1980 Commissioner of the Japan Patent Office ■ Case Indication 1982 Patent Application No. 16525 2 Name of invention 4) Exchanger 3 Person who makes amendment Related Patent Applicant: 1-1 Showa-cho, Kariya-shi, Aichi Prefecture (426) Nippondenso Co., Ltd. Representative: Kengo Toda, 4th Director, 7-7 Showa-cho, Kariya-shi, Aichi Prefecture, 448, 6, Amendment Contents (1) "Adjustment" on page 8, line 15 of the specification and page 10, line 15 will be corrected to "preparation." (2) The word "protection" on page 9, line 14 and page 16, line 3 of the same book has been corrected to "capture." (3) In the first line of page 12 of the same book, "capacity" was corrected to "procedure". (4) "Figure 1" in the same book, page 12, line 10, "Figure 2"
I will correct it. (5) "Exchanger" will be deleted from lines 9 and 10 on page 18 and line 10 on page 21 of the same book. (6) In the 4th line of page 21 of the same book, "sheet" is corrected to "1 sticker." (7) "Structure" in line 10 of page 21 of the same book is corrected to "manufacturing." (8) "Figure 4" on page 24, line 6 of the same book is corrected to "Figure 1, Figure 3." (9) In the same book, page 25, line 3, [... is valid. ], insert the following sentence: [FIGS. 8 to 10 show an embodiment in which a holding groove 10a for the adhesive sealant 26 is formed in the resin tank mounting portion 10. In these embodiments, when the attachment portion 10 is fitted into the groove 20 of the core plate 16, it is possible to prevent the adhesive sealant 26 filled in the groove 20 from overflowing to the outside of the core plate I6. That is, the adhesive sealant 26 pushed out when the attachment part IO is inserted is accommodated in the holding groove 10a and does not overflow from the groove part 20. Further, according to this example, the contact area between the attachment portion 10 and the adhesive sealant 26 is increased, and the sealing performance is improved. (10) "Figure 7" on page 26, line 4 of the same book is corrected to "Figure 10." (11) Figures 8, 9, and 10 of the drawings will be added as shown in the attached sheet.

Claims (1)

[Scope of Claims] (1) A metal tube through which a heat exchange fluid flows, a metal core plate 1 fixed to the end of the tube, and a metal core plate 1 fixed to the core plate in a watertight manner and allowing fluid to flow in and out. 1. A heat exchanger comprising: a tank having a lobe, and wherein the core plate and the tank are fixed watertightly by an additional type liquid silicone rubber adhesive sealant. (2+The heat exchanger according to claim 1, in which a heat exchange fluid containing amine/ammonia flows in the duplex. (3) The heat exchanger according to claim 1, wherein the core plate is a brass layer. The heat exchanger according to claim 2. The heat exchanger according to claim 1 or 2, wherein the core plate is made of alumina. (5) The heat exchanger according to claim 1 or 2, wherein the core plate is made of aluminum. The heat exchanger according to claim 1, which is modulus and has an elongation of 400% or more. The shape is the adhesive sticker 3rd
The heat exchanger according to item 1 or 4. (7) The cross-sectional shape of the tank increases the joint area.
The heat exchanger according to item 1 or 4.