JP2005201570A - Tube base structure of heat exchanger and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tube base structure of a heat exchanger and its manufacturing method having superior durability near a base part while reducing circulation resistance of the fluid inside of a tube. <P>SOLUTION: In this tube base structure of the heat exchanger wherein a longitudinal end part 111a of the tube 111 having a flat square-shaped cross section, is fitted in a tube hole 121a formed on a header tank 120, and joined at a contact part 131 where the tube 111 and the header tank 120 are kept into contact with each other, the contact part 131 of the tube 111 and a minor side 111b of the flat square-shaped cross section near the contact part are formed into the circular arc shape projecting to an outer side. The circular arc shape is preferably formed in expanding an opening of the tube 111. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tube rooting structure of a heat exchanger and a method for manufacturing the same, and is effective when applied to an intercooler that cools combustion air (intake air) sucked into an internal combustion engine.

  As a conventional heat exchanger, as shown in Patent Document 1, there is an intercooler previously proposed by the present applicant. This intercooler cools combustion air (intake air) sucked into an internal combustion engine, and a plurality of tubes and outer fins are alternately stacked, and the longitudinal ends of the tubes are connected to a header tank. It is formed by. And the connection part of the tube with respect to a header tank, what is called a root part, is formed by a tube being inserted in the hole drilled in the core plate which comprises a part of header tank, and contact parts are brazed. (FIG. 4 in Patent Document 1).

Here, in a limited space, in order to increase the cross-sectional area of the tube as much as possible, reduce the flow resistance of the intake air flowing through the tube, and improve the cooling performance against the intake air, the cross-sectional shape of the tube Is formed into a flat square shape (FIG. 2 in Patent Document 1).
JP 2002-286395 A

  However, the stress generated in the tube due to the temperature and pressure of the intake air during the operation of the intercooler tends to concentrate particularly on the corners of the flat quadrangular cross section near the root portion, leaving a difficulty in terms of durability.

  In view of the above points, the present invention is to provide a tube rooting structure for a heat exchanger that is excellent in durability near the root portion while reducing the flow resistance of the internal fluid of the tube, and a method for manufacturing the same.

  In order to achieve the above object, the present invention employs the following technical means.

  In the first aspect of the present invention, the longitudinal end (111a) of the tube (111) having a flat rectangular cross section is fitted into the tube hole (121a) formed in the header tank (120), and the tube ( 111) and the header tank (120) in the tube rooting structure of the heat exchanger joined at the abutting portion (131) that abuts each other, the abutting portion (131) of the tube (111) and a flat rectangular cross section in the vicinity thereof The short side (111b) is formed to have an arc shape protruding outward.

  Thereby, the corner (111d) of the flat rectangular cross section of the tube (111) in the vicinity of the root (130) formed by joining the tube (111) and the header tank (120) at the contact portion (130). The angle can be increased. Therefore, the stress generated in the vicinity of the root portion (130) of the tube (111) due to the temperature and pressure during the operation of the heat exchanger (100) acts evenly on the arc-shaped short side (111b) portion. Since the stress concentration on the corner portion (111d) is alleviated, the durability in the vicinity of the root portion (130) of the tube (111) can be improved.

  In addition, in the general part which occupies most other than the root part (130) of the tube (111), since the flat square cross section is maintained, the effect of reducing the flow resistance of the fluid flowing through the tube (111) can be maintained. .

  In the invention according to claim 2, the arc-shaped radius (R1) of the short side (111b) of the flat rectangular cross section is set to be larger than ½ of the distance (W) between the long sides (111c). It is characterized by that.

  As a result, the vicinity of the root portion (130) of the tube (111) can be kept as close as possible to the flat rectangular cross section that is the basic shape, and durability can be improved.

  The invention according to claim 3 is characterized in that the tube (111) and the header tank (120) are used for an intercooler (100) for cooling combustion air (intake air) sucked into the internal combustion engine. In the operation of the heat exchanger (100), the present invention is particularly suitable for an intercooler (100) that is highly susceptible to thermal stress due to high intake air temperature.

  In the invention according to claim 4, the tube end formed in the core plate (121) forming a part of the header tank (120) in the longitudinal direction end portion (111 a) of the tube (111) having a flat rectangular cross section. (121a), the longitudinal end (111a) of the tube (111) is expanded to the tube hole (121a) side by insertion of the magnifying jig (200), and the tube (111) and the core plate ( 121) is a method for manufacturing a tube root portion of a heat exchanger that joins abutting portions (131) that abut each other, and when expanding, the abutting portion (131) and the tube (111) in the vicinity thereof The short side (111b) of the flat rectangular cross section is formed into an arc shape protruding outward.

  Thereby, when expanding a normal tube (111), a short side (111b) part can be simultaneously formed in circular arc shape, and the tube rooting structure of the heat exchanger of Claims 1-3 is easily made It can be.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment description mentioned later.

(First embodiment)
In the present embodiment, the tube rooting structure for a heat exchanger according to the present invention is applied to an air-cooled intercooler 100, which will be described below with reference to FIGS. 1 is a front view showing an intercooler 100 according to the present embodiment, FIG. 2 is a sectional view showing an AA portion in FIG. 1, FIG. 3 is a sectional view showing a B portion in FIG. 3 is an arrow view showing the tube 111 as viewed from the direction C in FIG. 3, FIG. 5 is an external perspective view showing a single state of the tube 111, and FIG. 6 is an external perspective view showing a tube opening process when the intercooler 100 is manufactured. It is.

  The intercooler 100 is a heat exchanger that cools combustion air (hereinafter, intake air) sucked into a vehicle engine (internal combustion engine) by heat exchange with cooling air from the outside. The intercooler 100 mainly includes a core portion 110 and a pair of header tanks 120. Each member described below is made of aluminum or an aluminum alloy, and the contact portions of the members are joined by brazing or welding. Is formed.

  As shown in FIGS. 1 and 2, the core portion 110 is formed by alternately stacking tubes 111 having inner fins 114 inserted therein and outer fins 112, and side plates 113 are arranged at both outermost sides in the stacking direction. It is arranged and formed.

  The tube 111 is a pipe member through which the intake air circulates, and in order to increase the cross-sectional area as much as possible in a limited space and reduce the flow resistance of the intake air, the cross-sectional shape should be a flat square shape. ing. The inner fin 114 inserted into the tube 111 is formed into a wave shape from a thin flat plate, gives a turbulent flow effect to the flow of intake air, and improves the heat transfer coefficient on the intake side. In addition, since the cross-sectional shape of the tube 111 is a flat square shape, the inner fin 114 is efficiently accommodated without generating a dead space in the tube 111.

  Like the inner fin 114, the outer fin 112 is formed into a wave shape from a thin flat plate, and a plurality of louvers 112a formed by cutting and raising are provided on the flat surface portion, and the heat radiation area to the cooling air side is increased. While expanding, the turbulent flow effect by the louver 112a is acquired, and the heat exchange with intake air is promoted.

  The side plate 113 is a reinforcing member that extends in the longitudinal direction of the tube 111, has a substantially U-shaped cross-section, and a rib that extends in the longitudinal direction is provided at the inner center of the U-shape.

  Incidentally, the tube 111 is obtained by bending a plate material in which a brazing material is clad (covered) in advance on both the front and back surfaces and electrically welding the end portions to each other. The tube 111 is brazed with a material. Further, a brazing material is clad in advance on the surface of the side plate 113 on the outer fin 112 side, and the outermost outer fin 112 is brazed to the side plate 113 by this brazing material.

  A pair of header tanks 120 extending in the stacking direction of the tubes 111 and communicating with each tube 111 are provided on both longitudinal end portions 111 a (hereinafter referred to as tube end portions 111 a) of the tubes 111. The header tank 120 includes a core plate 121 to which the tube 111 is joined, and a tank body 122 that is welded to the core plate 121 to form a tank internal space.

  As shown in FIGS. 3 and 6, the core plate 121 is provided with an edged portion 121b on the long side of an elongated flat plate whose brazing material is clad in advance on both the front and back surfaces, and a tube at a portion corresponding to the tube end 111a. A hole 121a is provided. The tube end portion 111a is fitted into the tube hole 121a, and the tube 111 and the core plate 121 are brazed with a brazing material clad on the tube 111 and the core plate 121 at a contact portion 131 that contacts each other. The brazed portion in the contact portion 131 is formed as a so-called root portion 130 of the tube 111. Note that both end portions of the side plate 113 in the longitudinal direction are brazed to the core plate 121 with a brazing material coated on the core plate 121.

  In the present invention, the shape of the tube 111 in the vicinity of the root portion 130 is characterized. That is, as shown in FIGS. 4 and 5, with respect to the flat rectangular cross section which is the basic shape of the tube 111, in the vicinity of the root portion 130, the short side 111b has an arc shape protruding outward. Yes. Further, the radius R1 of the arc shape is set to be larger than ½ of the distance W between the long sides 111c.

  Specifically, the short side 111b is formed by an arc having a radius (R1) of 8.6 mm with respect to the tube 111 having a long side direction dimension of 65 mm and a short side direction dimension of 8.9 mm. In addition, the intersection part (corner part 111d) of the long side 111c and the circular arc is connected by R having a radius of 2 mm.

  As described above, the core plate 121 to which the tube 111 is connected is opened to the core plate 121 side as shown in FIG. 1, and the opening 122a is formed on one longitudinal end side. A tank body 122 forming a container body is welded. The right header tank 120 in FIG. 1 distributes and supplies intake air to each tube 111, and the left header tank 120 in FIG. 1 collects and collects intake air flowing out from the tube 111.

  Next, a schematic manufacturing method of the intercooler 100 will be described. First, a tube 111 formed by bending a plate material and electric welding, and an outer fin 112, a side plate 113, an inner fin 114, and a core plate 121 formed by pressing are prepared in advance. In addition, the cross-sectional shape of the tube 111 is shape | molded by flat square shape over the full length at this time. Moreover, the tube hole 121a of the core plate 121 is shape | molded by the shape corresponding to the cross-sectional shape of the tube 111 demonstrated in FIG. 4, FIG.

  Then, the inner fin 114 is inserted into the tube 111 and pressed in the direction of the short side 111b of the tube 111, so that the inner wall of the long side 111c of the tube 111 is surely in contact with the inner fin 114.

  Then, using a lamination jig (not shown) as a guide, the side plate 113 is set on the lowermost side, and a predetermined number of layers are alternately laminated on the upper side in the order of the outer fin 112, the tube 111, and the outer fin 112. Another side plate 113 is set on the upper side of the upper outer fin 112 to assemble the core portion 110.

  Then, the tube end portion 111a is fitted into the tube hole 121a of the core plate 121, and the core plate 121 is driven by a press machine (not shown).

  Then, as shown in FIG. 6, the magnifying jig 200 is inserted from the side of the tube end portion 111 a protruding from the core plate 121, and the vicinity of the tube hole 121 a (the root portion 130) of the tube 111 is expanded. The magnifying jig 200 includes a main body part 210 and a magnifying part 220 having two projecting parts. The outer periphery of the magnifying part 220 in the vicinity of the main body part 210 side is the tube 111 described in FIGS. 4 and 5. Are formed so as to correspond to the cross-sectional shape (the short side 111b is an arc shape). Therefore, with this magnifying jig 200, the short knitting 111b of the tube 111 is formed in an arc shape in the vicinity of the tube hole 121a (the root portion 130), and the entire circumference of the cross section of the tube 111 is reliably brought into contact with the tube hole 121a side. As a result, it is expanded (the contact portion 131 is formed).

  And the state where the core plate 121 was assembled | attached to the core part 110 with the jig | tool, such as a wire, is hold | maintained, after degreasing and flux application | coating, it throws in in a brazing furnace and brazes integrally.

  Further, the tank body 122 formed by casting is welded to the core plate 121, and thereafter, predetermined inspections such as leakage inspection (check for brazing failure and welding failure) and dimensional inspection are performed to complete the manufacture of the intercooler 100. To do.

  Next, the operation | movement and effect of the intercooler 100 based on the said structure are demonstrated. In the intercooler 100, intake air flows from the right opening 122a in FIG. 1, flows through the tubes 111 from the right header tank 120, and is cooled by heat exchange with external cooling air. Then, it flows out from the left side opening 122a to the vehicle engine side through the left side header tank 120 in FIG. Incidentally, the intake air flows into the intercooler 100 at a temperature of about 200 ° C., and is cooled to about 50 ° C. by the heat exchange.

  By the way, when the intercooler 100 is operated as described above, stress due to repeated application of intake air temperature and pressure (internal pressure) acts on the tube 111. In the prior art, stress concentrates on the corner portion 111d of the tube 110 having a flat rectangular cross section, particularly in the vicinity of the root portion 130, leaving a difficulty in durability. Since the short side 111b of the tube 111 is formed to have an arc shape, the angle of the corner portion 111d can be increased. Therefore, the stress generated in the vicinity of the root portion 130 of the tube 111 due to the temperature and pressure at the time of operation of the intercooler 100 acts evenly on the short side 111b of the arc shape, Since the stress concentration is relaxed, the durability in the vicinity of the root portion 130 of the tube 111 can be improved.

  Further, since the radius R1 of the arc shape forming the short side 111b is set to be larger than ½ of the distance W between the long sides 111c, the vicinity of the root portion 130 of the tube 111 is as basic as possible. Durability can be improved by keeping the shape close to a flat rectangular cross section.

  By the way, according to the analysis by the inventor's desktop calculation, the stress value generated in the corner portion 111d is reduced by 8% when the intake air temperature is repeatedly applied at 20 ° C. to 200 ° C., and the internal pressure due to the intake air is 0-3. It was confirmed that 7% was reduced by repeated addition of 5 bar.

  In addition, in the general part which occupies most other than the root part 130 of the tube 111, since the flat square cross section is maintained, the effect of reducing the flow resistance of the intake air flowing through the tube 111 can be maintained.

  Moreover, since the arc shape of the short side 111b of the tube 111 is formed simultaneously with the opening of the normal tube 111, the intercooler 100 having the tube rooting structure of the present invention can be easily obtained. it can.

(Other embodiments)
In the above embodiment, the present invention is applied to the intercooler 100, but the present invention is not limited to this, and can be applied to other heat exchangers (for example, a condenser, a radiator, and the like).

  Further, the arc shape of the short side 111b of the tube 111 is not limited to the one formed in the magnifying process, and may be formed in a single state after the tube 111 is formed.

It is a front view which shows the intercooler which concerns on this embodiment. It is sectional drawing which shows the AA part in FIG. It is sectional drawing which shows the B section in FIG. It is an arrow line view which shows the tube seen from the C direction in FIG. It is an external appearance perspective view which shows the single-piece | unit state of a tube. It is an external appearance perspective view which shows the tube port expansion process at the time of intercooler manufacture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Intercooler 111 Tube 111a Longitudinal direction end part 111b Short side 111c Long side 120 Header tank 121 Core plate 121a Tube hole 131 Contact part 200 Opening jig

Claims (4)

A longitudinal end (111a) of the tube (111) having a flat rectangular cross section is fitted into a tube hole (121a) formed in the header tank (120), and the tube (111) and the header tank (120 In the tube rooting structure of the heat exchanger joined at the abutting portions (131) that abut each other,
The heat exchange, wherein the abutting portion (131) of the tube (111) and the short side (111b) of the flat rectangular cross section in the vicinity thereof are formed to have an arc shape protruding outward. The rooting structure of the vessel.   The heat exchange according to claim 1, wherein the radius (R1) of the arc shape is set to be larger than ½ of a distance (W) between long sides (111c) of the flat rectangular cross section. Tube tube rooting structure.   The said tube (111) and the said header tank (120) are used for the intercooler (100) which cools the combustion air (intake | air_intake) inhaled by an internal combustion engine, The Claim 1 or Claim 2 characterized by the above-mentioned. The tube rooting structure of the heat exchanger as described in 1. The longitudinal end (111a) of the tube (111) having a flat rectangular cross section is inserted into the tube hole (121a) formed in the core plate (121) forming a part of the header tank (120),
By inserting the magnifying jig (200), the longitudinal end portion (111a) of the tube (111) is expanded toward the tube hole (121a),
The tube (111) and the core plate (121) are a method for manufacturing a tube root portion of a heat exchanger that joins a contact portion (131) that contacts each other,
When performing the magnifying, the short side (111b) of the flat rectangular cross section of the tube (111) in the contact portion (131) and the vicinity thereof is formed into an arc shape protruding outward. A method for manufacturing a tube root portion of a heat exchanger.

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