JP2006234318A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger capable of preventing opening of a caulking portion, and cracking of a brazed portion of a tube in accompany with the increase of internal pressure of a header tank. <P>SOLUTION: The header tank 1 of this heat exchanger is formed by caulking and connecting a core plate 2 with which an end portion of the tube 4 is connected by brazing, and a tank main body 3 covering a core plate in a state of forming a tank space 1a, and the core plate is composed of two parts, that is, a tube connecting member 2A connected with the tube end portion and composed of an AL material of high brazing property, and a caulking joining member 2B at a connection side with the tank main body composed of AL material of high strength. The connecting member and the joining member are joined by brazing at their peripheral edge overlapped portions, and the caulking portion 22 is formed on the joining member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat exchanger, and is particularly suitable for heat exchange for cooling engine coolant.

  Generally, a heat exchanger used for a radiator or the like has a core portion made up of a large number of tubes arranged in parallel and a large number of corrugated or plate-like fins arranged between the tubes through which a fluid flows. These tubes are mainly composed of header tanks connected at both ends in the longitudinal direction. In this case, the header tank is formed of a core plate to which many tubes are connected and a tank body that covers the core plate and forms a tank space. The connection structure between the core plate and the tube is generally such that the hole edge of the tube insertion hole of the core plate forms a burring portion raised to the tank side by burring, and the end of the tube is inserted into this burring portion. The core plate and the tube are joined by brazing.

  In addition, the connection structure between the core plate and the tank body is obtained by caulking a claw piece for caulking provided on the outer edge portion of the core plate to the end of the tank body by pressing as shown in Patent Document 1, It is fixed by caulking. That is, as shown in FIG. 2 (a), the core plate 2 of the header tank 1 is formed with grooves 21 along the four sides of the outer edge, and the tip of the outer edge extends over the entire circumference. A plurality of claw pieces (caulking portions) 22 for caulking are formed. On the other hand, a stepped portion 32 is formed on the opening end surface 31 of the tank body 3 of the header tank 1. In this way, the packing 6 is press-fitted into the groove portion 21 of the core plate 2, the opening end surface 31 of the tank body 3 is pushed from above, and the claw pieces 22 of the core plate 2 are pressed onto the stepped portion 32 of the opening end surface 31 by pressing. By crimping, the core plate 2 and the tank body 3 are integrally coupled. Thus, in the prior art, the tank body 3 is fixed to the heat exchanger core portion by caulking the claw pieces 22 of the core plate 2, and the cooling water flowing in the tank is held.

  However, in recent years, the internal pressure in the radiator tank has become very high due to higher engine output and propulsion of diesel vehicles in Europe. When used for a long time under such a high internal pressure, the expansion of the tank deforms the caulking portion of the core plate 2 as shown by the broken line in FIG. Cracks occur in the brazed portion with the plate 2 and often causes the problem of cooling water leakage.

  As countermeasures for the above problems, the tank thickness has been increased by increasing the thickness of the tank body or adding ribs to the tank body, and the rigidity of the core plate has been increased by increasing the thickness of the core plate. However, it takes a lot of cost and time, such as new molding molds, equipment changes, and material costs.

  The present invention has been made in view of the above problems, and its object is to caulk the core plate and the tank main body without requiring a large amount of expenses due to new installation of molds, equipment changes, material costs, etc. By providing a heat exchanger capable of increasing the rigidity of the portion, increasing the thickness of the core plate and increasing the strength, and suppressing the opening of the caulking portion and cracking of the brazed portion of the tube. is there.

This invention provides the heat exchanger as described in each claim of a claim as a means for solving the said subject.
In the heat exchanger according to claim 1, the header tank is formed by caulking and joining a core plate having a tube end connected by brazing and a tank body covering the core plate so as to form a tank space. This core plate is made up of two parts that are made of aluminum with good brazing on the connection side to the tube end and high-strength aluminum on the connection side with the tank body. With this, the rigidity of the caulking joint portion between the core plate and the tank body can be increased, and caulking opening due to the increase in the internal pressure of the header tank can be suppressed.

In the heat exchanger according to claim 2, the peripheral edge of the aluminum material having a good brazing property and the peripheral edge of the high-strength aluminum material are overlapped, and the overlapped portion is joined by brazing. It is possible to increase the thickness of the core plate and increase the strength of the core plate, to prevent cracking of the brazed portion between the core plate and the tube, and to prevent fluid leakage from the portion.
In the heat exchanger according to claim 3, a groove portion and a caulking portion are formed on the high-strength aluminum material side of the core plate. The core plate and the tank body are caulked and joined by pressing the open end of the tank body from above and caulking the core plate onto the stepped portion of the tank body. As a result, since the caulking structure is the same as that of the prior art, it is possible to obtain a caulking joint having sufficient strength to withstand a high internal pressure without the need for large equipment modification.
According to the invention described in claim 4, the core plate has a tube connecting member to which the tube is connected, and a caulking connecting member that is caulked and coupled to the tank body and is made of a material having higher strength than the tube connecting member. Features. As a result, it is possible to increase the rigidity of the caulking joint between the core plate and the tank body while securing the brazing property between the tube and the core plate, and to suppress the caulking opening due to the increase in the internal pressure of the header tank. it can.

  Hereinafter, a heat exchanger according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1A is an exploded perspective view showing a main part of the heat exchanger according to the embodiment of the present invention, and FIG. 1B is a cross-sectional view of the main part. The heat exchanger according to the present invention includes a plurality of tubes 4 that are arranged in parallel and through which fluid (cooling water) flows, corrugated or plate-like fins 5 provided between the tubes 4, and both ends of the tubes 4. And a header tank 1 for distributing and collecting fluids. In this heat exchanger, heat exchange is performed between the fluid passing through the tube 4 and the gas passing through the fins 5 outside the tube 4, and the header tank 1 distributes the fluid flowing through the plurality of tubes 4. I'm gathering. Each of the header tanks 1 is formed with an opening (not shown). One of the openings is on the fluid inflow side and the other is the fluid outflow side. The tube 4 and the fin 5 form a core part.

  The header tank 1 includes a core plate 2 connected to the tube 4 and a tank body 3 that covers the core plate 2 and forms a tank space 1a. The core plate 2 is composed of two parts: a tube connecting member 2A to which the tube 4 is connected, and a caulking coupling member 2B that caulks and couples the core plate 2 and the tank body 3. The tube connecting member 2A is formed of an aluminum (AL) material having good brazeability, for example, BA90PC (a special material dedicated to DENSO Corporation) and the like, because it is necessary to be connected to the tube 4 by brazing. The coupling member 2B is formed of a high-strength aluminum (AL) material in order to be caulked and coupled to the tank body 3. The tube connecting member 2A and the caulking coupling member 2B are coupled by overlapping the peripheral edge of the caulking coupling member 2B on the peripheral edge of the tube connecting member 2A and brazing the overlapping portion. The AL material in this case naturally includes an aluminum alloy material.

  The tube connecting member 2A has a flat plate shape and is provided with a large number of insertion holes for inserting and connecting the ends of the tubes 4. The hole edge portions of these insertion holes form a burring portion 23 raised to the tank side by burring. Therefore, the end of the tube 4 is inserted into the burring portion 23, and the tube 4 and the tube connecting member 2A of the core plate 2 are joined by brazing.

  The caulking coupling member 2B has a substantially bowl shape as a whole in which the groove portion 21 is formed. One of the peripheral edges is connected to the tube connecting member 2A, and the other peripheral edge has a large number at the tip of the outer edge. A caulking portion (claw piece) 22 is formed.

  The tank body 3 has a shape like a substantially rectangular bowl with one side opened, and a step 32 protruding outward is formed on the opening end surface 31 thereof. In FIG. 1 (a), the core plate 2 and the tank body 3 constituting the tank head 1 are shown with their longitudinal ends cut off. Both ends are structured to be closed, and the same structure as that of the side, that is, the core plate 2 has a groove portion 21 and a caulking portion 22, and the tank body 3 has a step portion 32.

  In the coupling between the core plate 2 and the tank body 3, the packing 6 is inserted into the groove 21 in the caulking coupling member 2 </ b> B of the core plate 2, and the opening end surface 31 of the tank body 3 is positioned on the packing 6. Then, the tank body 3 is assembled to the core plate 2, and the caulking portion 22 of the caulking coupling member 2B is caulked and fixed on the step portion 32 of the opening end surface 31 by press working in a state where the opening end surface 31 is crimped to the packing 6. To do. As a result, the core plate 2 and the tank body 3 are joined together, and the packing 6 is elastically compressed and deformed to be crimped to the opening end surface 31 and the groove 21.

  In this embodiment, since the core plate 2 and the tank body 3 are joined by caulking, the tank body 3 is excellent in heat resistance and strength resistance, such as nylon containing a reinforcing material such as glass fiber. It can be molded with a resin material. Therefore, the header tank 1 having a light weight and sufficient strength can be obtained.

As described above, in this embodiment, the core plate 2 is composed of two parts, that is, the tube connecting member 2A for connecting the tube 4 and the caulking connecting member 2B for connecting to the tank body 3 by caulking, and the tube connecting member. AL material with good brazing property is used for 2A, and high-strength AL material is used for the caulking coupling member 2B. Thereby, the rigidity of the caulking part 22 which is a joint part of the core plate 2 and the tank main body 3 can be increased with respect to the prior art, and the caulking opening caused by the increase in the internal pressure of the header tank 1 can be suppressed.
In addition, since an AL material having a better brazing property than a high-strength AL material having a poor brazing property is generally used for the brazing portion of the tube 4, the brazing portion between the tube 4 and the core plate 2 is used. Problems such as fluid leakage can be avoided.
Furthermore, since the core plate 2 is formed by overlapping the peripheral edges of the tube connecting member 2A and the caulking coupling member 2B and brazing the overlapping portion, the thickness of the core plate 2 is increased and the strength is increased. be able to.

  As described above, in the present invention, fluid leakage failure from the tank seal surface can be avoided by reinforcing the caulking portion. Moreover, in this invention, since the core plate has a two-part configuration, the structure is similar to that of the conventional product, and therefore, there is an effect that a large facility remodeling investment is not required.

(A) is an exploded view of the principal part of the heat exchanger of embodiment of this invention, (b) is sectional drawing of the principal part. (A) is principal part sectional drawing and the partial enlarged view of the heat exchanger of a conventional structure, (b) is a figure explaining the problem of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Header tank 2 Core plate 2A Tube connection member 2B Caulking coupling member 21 Groove part 22 Caulking part (claw piece)
23 Burring part 3 Tank body 31 Open end face 32 Step part 4 Tube 5 Fin

Claims (4)

A plurality of tubes arranged in parallel, forming fluid passages, fins provided between the tubes, and header tanks arranged at both ends in the longitudinal direction of the tubes and distributing and collecting fluids, In the heat exchanger in which the header tank is formed by caulking and joining a core plate to which an end portion of the tube is connected by brazing and a tank body covering the core plate so as to form a tank space,
The core plate is composed of two parts that are made of an aluminum material having a good brazing property on the connection side with the tube end and a high-strength aluminum material on the connection side with the tank body. Exchanger.   2. The heat exchange according to claim 1, wherein a peripheral edge of the high-strength aluminum material is overlapped with a peripheral edge of the aluminum material having a good brazing property, and the overlapping portion is joined by brazing. vessel.   A groove portion and a caulking portion are formed on the high-strength aluminum material side of the core plate, while a step portion is formed at the opening end portion of the tank body, and a packing is press-fitted into the groove portion, The opening end of the tank main body is pushed in from above, and the caulking portion of the core plate is caulked onto the stepped portion of the tank main body, whereby the core plate and the tank main body are caulked and combined. The heat exchanger according to claim 1 or 2. A plurality of tubes arranged in parallel, forming fluid passages, fins provided between the tubes, and header tanks arranged at both ends in the longitudinal direction of the tubes and distributing and collecting fluids, In the heat exchanger in which the header tank is formed by caulking and joining a core plate to which an end portion of the tube is connected by brazing and a tank body covering the core plate so as to form a tank space,
The core plate includes a tube connection member to which the tube is connected, and a caulking connection member that is caulked and coupled to the tank body and is made of a material having higher strength than the tube connecting member. .

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