JPH01127897A - Heat exchanger for automobile - Google Patents

Abstract

PURPOSE:To prevent stress corrosion breakage of a seat plate at a connection part between the seat plate and a tank made of resin, softening by heating, and leakage of liquid and to improve reliability, by a seat plate is formed by a copper alloy containing a specified amount of one or more of tin, phosphor, lead, zinc and nickel. CONSTITUTION:A fin 2 is mounted between a plurality of tubes 1 through which heating medium flows to form a core 3, and seat plates 4 and 4' are situated to both ends of the tubes 1 of the core 3 to cover tanks 5 and 5' made of resin having the one open end. In this case, the seat plates 4 and 4' are formed by a copper alloy containing 0.04-3.0 wt.% in a total of one or more kinds selected from a group of 0.01-0.5wt.% tin, 0.002-0.1wt.% phosphor, 0.003-0.3 wt.% lead, 0.003-3.0wt.% zinc, and 0.005-1.0wt.% nickel, and a rest of copper. U- grooves 6 are formed in the outer peripheral edges of the seat plates 4 and 4', and the opening edges 5a of the tanks 5 and 5' made of resin are securely engaged internally of the U-grooves 6 through a sealing material 7.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a heat exchanger for an automobile that is suitably used as a radiator for engine cooling or a heater for space heating, and particularly when a resin tank is used. The present invention relates to a highly reliable heat exchanger for automobiles that does not soften during soldering and is free from stress corrosion cracking and liquid leakage at the joint between the tank and the seat plate.

[Prior Art] FIG. 1 shows the most typical structure of a radiator as a heat exchanger for an automobile. In FIG. 1, corrugated copper fins 2 are soldered to form a core 3 between a plurality of brass tubes 1 through which a heat exchange medium for engine cooling flows.

Seat plates 4.4° are provided at both ends of the tube 1 of the core 3, and the opening edge of a tank 5.5° is fixed to each of the seat plates 4.4-.

In recent years, there has been a growing demand for lighter vehicle bodies, and in response to this demand, the tank 5.5'' has been constructed of resin. In this case, the joint between the seat plate and the tank is, for example, the second
As shown in the figure, the outer peripheral edge of the seat plate 4.4 is bent to form a U groove 6, and the opening edge 5a of the resin tank 5.5'' is inserted into the U groove 6.
are fitted and caulked through the sealing material 7, or as shown in FIG. Part 5b
are fitted and fixed.

[Problems to be solved by the invention] By the way, the above-mentioned seat plate has a zinc content of 30 to 3
5% by weight of alpha brass material is used, and alpha brass material is known as an inexpensive material with excellent strength and good workability.

However, the seat plate is usually annealed after press forming.
Although residual stress during molding is removed, radiators using resin tanks still experience stress during use.
It has been reported that cracks (a type of stress corrosion cracking) occur from inside the seat plate.

On the other hand, pure copper is known to have excellent resistance to stress corrosion cracking, but when soldering tubes and fins, the seat plate may soften due to heating, and during use, high-temperature media (over 80℃) It cannot be used because the circulation of water reduces the liquid sealing ability of the joint and causes liquid leakage. .

For this reason, an attempt has been made to strengthen the joint between the seat plate and the tank by caulking an iron or stainless steel fixing plate 8 arranged along the U-side 6, as shown in Fig. 4. However, the use of a fixed plate is not preferable from the perspective of reducing the weight of the vehicle, and also leads to increased costs such as material costs and processing costs.

Therefore, an object of the present invention is to provide a highly reliable automobile heat exchanger that is free from stress corrosion cracking of the seat plate, softening due to heating, and liquid leakage at the joint between the seat plate and the resin tank. It is something to do.

[Means for Solving the Problems] The present invention has been made as a result of intensive studies in view of the above circumstances. To explain the structure of the present invention with the drawings, a core 3 is formed by installing fins 2 between a plurality of tubes 1 through which a heat exchange medium flows (FIG. 1), and seat plates 4 are attached to both ends of the tubes 1 of the core 3. In the automobile heat exchanger in which the seat plate 4.4- is provided with a resin tank 5.5- which is open at one end and covered with the resin tank 5.5-
0.01 to 0.5% by weight of tin, 0.002 to 0.00% by weight.
1% by weight phosphorus, 0.003-0.3% by weight lead, 0.
003 to 3.0% by weight of zinc, and 0.005 to 1.0% by weight.
The seat plate is made of a copper alloy containing at least one kind selected from the group consisting of 0% by weight of nickel in a total range of 0.04 to 3.0% by weight, and the remainder being substantially copper; A U-shape 6 is formed on the outer peripheral edge of the tank 4.4-, and the opening edge 5a of the resin tank 5.5° is fitted and fixed inside the U-shape 6 via a sealing material 7.

[Function] Cracks that occur in seat plates made of α-brass material are a type of stress corrosion cracking, resulting in brittle fracture along the brass grain boundaries. Stress corrosion cracking is usually caused by ammonia, but It is known that antifreeze media and water are also caused by high temperature conditions during radiator operation. In particular, when a resin tank is used, this tendency is remarkable in the U-shaped sections around the outer edge of the seat plate, and it is thought that this is caused by the addition of various external factors to the residual stress during machining or joining of the U-shaped sections. ing.

In the copper alloy used as the seat plate material in the present invention, it is not necessarily clear how individual component elements act, but each component element such as tin, phosphorus, lead, zinc, and nickel stably strengthens grain boundaries. It is thought that this will contribute to improved strength, dramatically improve resistance to stress corrosion cracking, and heat resistance.

[Effect of the invention] The automotive heat exchanger of the present invention has a seat plate made of tin, phosphorus, lead,
Since it is constructed from a copper alloy containing specific amounts of one or more of zinc and nickel, it is highly reliable without stress corrosion cracking, softening due to heating during soldering, or leakage due to long-term circulation of high-temperature media. In addition, due to the greatly improved susceptibility to stress corrosion cracking, there is no need for an annealing process after press forming the seat plate, and there is no need to fix it using iron or stainless steel fixing plates, so the manufacturing process can be simplified and is highly economical.

[Example] Hereinafter, an example in which the present invention is applied to a radiator of an automobile will be explained with reference to the drawings. In Fig. 1, reference numeral 1 denotes a plurality of brass tubes through which a heat exchange medium for engine cooling flows, and between these tubes 1 are copper fins 2 processed into a corrugated shape.
are attached by soldering to form the core 3. A seat plate of 4.4° is provided at both ends of the tube 1 of the core 3,
Each of the seat plates 4 and 4 has a resin tank 5 with one end open.
．． 5゛ is covered and sealed tightly.

The above seat plate 4.4- contains 0.01 to 0.5% by weight of tin,
0.002-0.1% by weight of phosphorus, 0°003-0.3
one or more selected from the group consisting of 0.003 to 3.0 weight % of lead, 0.003 to 3.0 weight % of zinc, and 0.005 to 1.0 weight % of nickel, in a total of 0.04 to 3.0 weight %. %, and the remainder is made of a copper alloy consisting essentially of copper.

If the content of the component elements is less than the above range, the desired strength will not be obtained, and even if more than the above range is added, the effect will not change, and on the contrary, there is a risk of impairing the formability of the seat plate. Undesirable.

For the resin tank 5.5'', 6-nylon reinforced with glass fiber or the like is preferably used.

In FIG. 2, in FIG. 0 showing the details of the joint between the seat plate 4 and the resin tank 5, the seat plate 4 has a U-shaped groove 6 formed by bending the outer periphery. A sealing material 7 is disposed at and fits into the opening edge 5a of the resin tank 5, which is covered from above the seat plate 4. The opening edge 5a has a thick rectangular cross section, and the edge 6 of the U groove 6 covers it.
Caulk a to secure it tightly. The same applies to the connection between the seat plate 4' and the resin tank 5-.

In addition, the connection between the seat plate 4.4" and the resin tank 5.5" is as follows.
As shown in FIG. 3, a fitting hole 6b is provided on the side edge of the U-shaped sleeve 6, and a convex portion 5b formed on the side wall of the opening edge 5a of the resin tank 5 is fitted into the fitting hole 6b. It may also be done by

Next, a radiator having the structure shown in FIGS. 1 and 3 was assembled using a copper alloy having the composition shown in Table 1 as a seat plate material, and a durability test was conducted. The resin tank was made of 6-nylon reinforced with short glass fibers, and the sealing material was a silicone rubber O-ring.

The radiator thus assembled was filled with a commercially available antifreeze medium for automobiles, and kept in a thermostat at 80° C. for 6 months. After checking for leaks, it was disassembled and inspected for cracks. The results are shown in Table 1.

As is clear from Table 1, the products of the present invention (Nos. 1 to 8) showed no cracking or leakage at all even after being kept for 6 months, while the comparative products (Nos. 9 to 10) Although there was no leakage, cracking occurred. In addition, cracks and leaks occurred in the conventional products (No. 11>), and it can be seen that by constructing the seat plate with a copper alloy having the composition shown in the present invention, the strength and heat resistance are dramatically improved. .

[Brief explanation of the drawing]

1 and 2 show one embodiment of the present invention, FIG. 1 is a front view of the radiator, FIG. 2 is an enlarged cross-sectional view of the joint between the seat plate and the resin tank, and FIG. 3 is the embodiment of the present invention. FIG. 4 is an enlarged cross-sectional view of a joint between a seat plate and a resin tank according to another embodiment of the present invention, and FIG. 4 is an enlarged cross-sectional view of a joint between a conventional seat plate and a resin tank. 1...Tube, 2...Fin 3...Core 4.4'...Seat plate 5.5-...Resin tank 5a...Opening edge 6...U 7...Sealing material Fig. 1

Claims (1)

[Claims] A heat exchanger for an automobile in which a core is formed by installing fins between a plurality of tubes through which a heat exchange medium flows, seat plates are provided at both ends of the tubes of the core, and a resin tank with one end open is covered. The seat plate is made of 0.01-0.5% by weight of tin, 0.002-0.1% by weight of phosphorus, 0.003-0.
One or more selected from the group consisting of 3% by weight of lead, 0.003 to 3.0% by weight of zinc, and 0.005 to 1.0% by weight of nickel, in total of 0.04 to 3.0%. % by weight, with the remainder being substantially copper, and a U-groove is formed on the outer peripheral edge of the seat plate, and the opening edge of the resin tank is inserted into the U-groove. A heat exchanger for an automobile, characterized in that it is fitted and fixed through a sealing material.