JP2000205786A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely close ends of a tube in a double tube oil cooler. SOLUTION: Longitudinal opposite ends of both tubes 3, 4 are closed with a cap 10 in which there is formed an opening section 10 through which oil flowing in a second tube 4 passes. Hereby, there is no need of closing the opposite ends of the tubes 3, 4 by plastically deforming (tube expansion) the opposite ends of the tubes 3, 4, so that even if a cross sectional configuration is flat, bad brazed joining is prevented from happening following tube expansion work. Thus, even when there is produced any gap between joints of two members constituting the tubes 3, 4, the opposite ends of the tubes 3, 4 can be securely closed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-pipe heat exchanger, and is effective when applied to an oil cooler for cooling oil such as engine oil and ATF (Automatic Transmission Fluid).

[0002]

2. Description of the Related Art As described in Japanese Patent Application Laid-Open No. 10-132474, for example, a double-pipe oil cooler supplies oil to a space between an outer cylinder (first tube) and an inner cylinder (second tube). The oil is cooled by flowing a cooling medium such as cooling water inside the second tube or outside the first tube and inside the first tube.

[0003] Both ends of both tubes are closed by plastically deforming (expanding) the second tube so as to expand toward the inner wall of the first tube.

[0004]

In recent years, there has been an increasing demand for downsizing oil coolers, and accordingly, the cross-section of both tubes has been reduced to a flat shape such as an ellipse or an ellipse. It is increasing. However, the flat cross section is not symmetric unlike the circular cross section,
The tube expanding operation for a tube having a flat cross section is more difficult to perform than the tube expanding operation for a tube having a circular cross section. For this reason, there is a high possibility that poor tube expansion occurs, and there is a possibility that poor joining (poor closing) of the two tubes may occur at the end portions of both tubes.

[0005] In view of the above, an object of the present invention is to reliably close the ends of both tubes in a double-pipe heat exchanger.

[0006]

The present invention uses the following technical means to achieve the above object. Claim 1
According to the invention described in Item 4, both ends of the tubes (3, 4) in the longitudinal direction are formed with a cap (1) having an opening (10a) through which the first fluid flowing through the second tube (4) passes.
0) It is characterized by being closed.

Thus, in the present embodiment, unlike those described in the section of the prior art, it is not necessary to close both ends of both tubes (3, 4) by plastic deformation (expansion). Therefore, even if the cross-sectional shape is flat,
Since no brazing failure occurs during the pipe expanding operation, the ends of both tubes (3, 4) can be reliably closed.

In the case where the tube is formed of two parts, the ends of the second tube (4) are plastically deformed (expanded), for example. If the blockage occurs, as will be described later, a gap is inevitably generated at the joint between the two components. This gap is inevitably generated when the tube is formed of two parts, and it is difficult to eliminate the gap structurally.

On the other hand, in the present invention, since both ends of both tubes (3, 4) are closed by caps (10), regardless of the presence or absence of the gap, both tubes (3, 4) are closed. Both ends can be reliably closed. In the invention according to claim 4, both tubes (3,
4) A fitting means (10b, 10c) for sandwiching at least one of the members from both sides in the thickness direction is provided.

As a result, the cap (10) and both tubes (3, 4) can be reliably pressed into contact with each other. Incidentally, the reference numerals in parentheses of the above means are examples showing the correspondence with specific means described in the embodiments described later.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present embodiment is an example in which the heat exchanger according to the present invention is applied to an oil cooler for cooling an engine oil (not shown) or an oil such as ATF for lubricating the inside of an engine (not shown). As shown in FIG. 1, the oil cooler 1 is disposed in the tank 101 such that its longitudinal direction matches the longitudinal direction of the tank 101 of the radiator 100 that cools the engine cooling water. In addition, FIG.
3 is an enlarged perspective view of the oil cooler 1. FIG.

FIG. 2A shows a cross section of the oil cooler 1 in a longitudinal direction, wherein 2 is a flow path through which oil (second fluid) flows, and the flow path 2 is arranged concentrically. An outer tube (hereinafter, referred to as a first tube) 3 formed in a flat aluminum tube and an inner tube (hereinafter, a second tube) formed in a flat tube and disposed in the first tube 3. (It is called a tube.)

On the other hand, since the engine cooling water (first fluid) flows outside the first tube 3 and inside the second tube 4, heat exchange between the oil flowing in the flow passage 2 and the engine cooling water occurs. Is performed. A well-known offset-type inner fin 5 for promoting heat exchange (cooling) of the oil is provided in the flow path 2, and the inner fin 5 is formed of aluminum to form the two tubes 3. , Brazed to 4.

An inflow port 6 for guiding oil discharged from the engine into the flow path 2 is formed at one end (right side of the paper) of the flow path 2, and cooled oil is provided at the other end side (left side of the paper). An outlet 7 for flowing out toward the engine is formed.
The inflow port 6 and the outflow port 7 open in a direction orthogonal to the longitudinal direction of the flow path 2, that is, toward the vehicle rear side (see FIG. 1).

Incidentally, reference numerals 8 and 9 denote aluminum brackets which are brazed to the first tube 3 to form the inlet 6 and the outlet 7, and which fix the oil cooler 1 in the tank 101 of the radiator 100. In FIG. 1, 8
Reference numerals a and 9a denote joints that are connected to the brackets 8 and 9 from outside the tank 101 of the radiator 100 and are connected to an oil pipe (not shown) from the engine.

As shown in FIG. 3, the first tube 3 is formed by brazing and joining a first member 3a and a second member 3b which are divided in a longitudinal direction of a cross section and press-formed into a predetermined shape. The first member 4a and the second member 4b, which are formed in the same manner as the first tube 3, are divided in the major axis direction of the cross section and press-formed into a predetermined shape.
Is formed by brazing.

In order to secure the contact area between the first member 3a and the second member 3b and to braze the two members 3a and 3b reliably, the first tube 3 is attached to the first member 3a and the second member 3b. On both sides in the major axis direction in parallel with the major axis direction
A protruding piece 3c protruding outward from the tube 3 is formed. On the other hand, in order to secure the contact area of the first member 4a and the second member 4b and to securely braze the two members 4a and 4b, the first member 4a and the second member 4b are provided with a long diameter direction of the second tube 4. Projecting pieces 4c are formed on both sides to project inward of the second tube 3 in parallel with the major axis direction.

As shown in FIG. 4, the first tube 3 (the first member 3a and the second member 3b) is depressed toward the second tube 4 (the first member 4a and the second member 4b). And a recess 3d having a through hole 3e formed in the bottom thereof.
Is provided, while the second tube 4 (the first member 4
a and the second member 4b), through the through hole 3e,
A burring portion 4d, which has been subjected to burring so as to protrude outward from the tube 3, is formed.

Then, with the burring portion 4d penetrating through the through hole 3e, the burring portion 4d is expanded radially outward of the through hole 3e, so that the concave portion 3d (first tube 3) and the burring portion 4d ( The second tube 4) is caulked and fixed. As shown in FIG. 2A, both ends of the tubes 3 and 4 in the longitudinal direction are closed by a cap 10 formed by press-molding an aluminum material. As shown, an opening 10a through which engine cooling water flowing through the second tube 4 passes is formed.

As shown in FIG. 2 (a), the cap 10 has a concave portion 10b depressed into the flow channel 2 from one end in the longitudinal direction of the flow channel 2 to the other end thereof, and a first tube 3 as shown in FIG. A protrusion 10c extending in the longitudinal direction thereof is formed in contact with the outer wall surface of the recess 10b.
The first tube 3 is sandwiched by Oc, thereby forming a fitting means for sandwiching the first tube 3 from both sides in the thickness direction.

The cap 10 is brazed to the cap 10 with a brazing material coated on the inner side of the oil cooler 1. Further, as shown in FIG. 5, the cap 10 is formed in a shape along the end surfaces of both tubes 3 and 4 so as to surely contact the end surfaces (surfaces perpendicular to the longitudinal direction) of both tubes 3 and 4. ing.

Next, the features of this embodiment will be described. In the oil cooler 1 according to the present embodiment, since both ends in the longitudinal direction are closed by the caps 10, both ends of the tubes 3 and 4 are plastically deformed (expanded) unlike those described in the section of the related art. ) Does not need to be closed.
Therefore, even if the cross-sectional shape is flat, a poor brazing connection due to the pipe expanding operation does not occur, and a poor connection (poor closing) between the tubes 3 and 4 occurs at the ends of the tubes 3 and 4. Can be prevented.

In the case where the first and second tubes 3 and 4 are formed by joining two parts (3a, 3b and 4a, 4b) as in the present embodiment,
If the second tube 4 is expanded and the second tube 4 and the first tube 3 are joined, a gap δ occurs at the joint A of the two parts as shown in FIG. The gap δ is inevitably generated when at least one of the tubes 3 and 4 is formed of two parts, and it is difficult to eliminate the gap δ structurally. .

On the other hand, in the present embodiment, since both ends of both tubes 3 and 4 are closed by caps 10, both ends of both tubes 3 and 4 are surely irrespective of the presence or absence of gap δ. Can be closed. In the present embodiment, the first side wall is formed by the side wall of the recess 10b and the protrusion 10c.
Since the first tube 3 is sandwiched from both sides in the thickness direction by sandwiching the tube 3, the cap 10
And the two tubes 3 and 4 can be securely pressed into contact with each other, and the cap 10 and both the tubes 3 and 4 can be reliably joined by brazing.

The cap 10 has a concave portion 1 which is depressed into the flow channel 2 from one end in the longitudinal direction of the flow channel 2 to the other end thereof.
Since 0b is formed, the cap 10 can be attached so as to be pressed into the flow path 2. For this reason, when the oil cooler 1 is heated in the furnace to braze the cap 10 and the tubes 3, 4, the cap 10 falls off from the tubes 3, 4 due to an increase in pressure in the flow path 2 or the like. Therefore, the cap 10 can be securely joined to the tubes 3 and 4 by brazing.

In the above-described embodiment, the heat exchanger according to the present invention is applied to an oil cooler for a vehicle. However, the present invention is not limited to this, and may be applied to other heat exchangers. be able to.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a state in which an oil cooler according to the present invention is disposed in a tank of a radiator.
(B) is a perspective view of the oil cooler.

FIG. 2A is a longitudinal sectional view of an oil cooler, and FIG. 2B is a front view of a cap.

FIG. 3 is an exploded perspective view of the oil cooler.

FIG. 4 is an enlarged view of a joining portion of a first member of the first tube and a first member of the first tube.

5A is a perspective view (partial cross section) of the cap 10 viewed from the flow channel 2 side, and FIG. 5B is a perspective view (partial cross section) of the cap 10 viewed from the outside.

FIG. 6 is a sectional view of the oil cooler when the second tube is expanded.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Oil cooler, 2 ... Flow path, 3 ... 1st tube, 4 ...
Second tube, 5 ... inner fin, 10 ... cap.

Continued on the front page (72) Inventor Akira Uchikawa 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Co., Ltd. ) Inventor Satomi Muto 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (4)

[Claims] 1. A flat tube-shaped first tube (3), and a flat tube-shaped second tube (3) disposed in the first tube (3).
A tube (4) and an opening (10a) through which the first fluid flowing through the second tube (4) is closed while closing both longitudinal ends of the tubes (3, 4). A heat exchanger comprising: a cap (10); and performing heat exchange between a second fluid flowing between the tubes (3, 4) and the first fluid. 2. A flat tube-shaped first tube (3), and a flat tube-shaped second tube (3) disposed in the first tube (3).
A tube (4) and a cap which closes both longitudinal ends of the tubes (3, 4) and has an opening (10a) through which a first fluid flowing through the second tube (4) passes; (1
0), heat exchange is performed between the second fluid flowing between the two tubes (3, 4) and the first fluid, and at least one of the two tubes (3, 4) is: A heat exchanger comprising two parts joined together. 3. A first tube (3) formed in a flat cylindrical shape, and a second flat tube (3) disposed in the first tube (3).
A tube (4) and an opening (10a) through which the first fluid flowing through the second tube (4) is closed while closing both longitudinal ends of the tubes (3, 4). A cap (10) for performing heat exchange between the second fluid flowing between the tubes (3, 4) and the first fluid; A heat exchanger characterized by being constituted by joining two parts. 4. The cap (10) is provided with fitting means (10b, 10c) for sandwiching at least one of the two tubes (3, 4) from both sides in the thickness direction. The heat exchanger according to any one of claims 1 to 3.