JP5082387B2 - Heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger, and is effective when applied to a radiator that cools cooling water by exchanging heat between cooling water and air of a water-cooled internal combustion engine.

  In the conventional heat exchanger, a large number of tubes and a large number of corrugated fins are alternately stacked to constitute a core portion. And the tank is arrange | positioned at the tube longitudinal direction edge part in the tube. This tank is composed of a core plate into which a tube is inserted, and a tank body part that is caulked and fixed to the core plate to form a space in the tank together with the core plate. In the core plate, a tube insertion hole into which a tube is inserted is formed in the tube joint surface, and a wall portion that is bent substantially perpendicular to the tube joint surface is formed on the outer periphery of the tube joint surface. Moreover, the insert which reinforces a core part is arrange | positioned at the edge part of a core part.

  In such a heat exchanger, when a temperature difference occurs between adjacent tubes, the tube joint surface of the core plate deforms like a bow in the tube longitudinal direction, and the tube root portion (that is, the tube root portion) There is a problem that stress concentrates on both ends in the tube width direction.

  On the other hand, a heat exchanger has been proposed in which ribs are formed on the tube joint surface of the core plate in parallel with the tube insertion holes, and both ends of the ribs are connected to the wall (for example, see Patent Document 1). . Thereby, the rigidity of a core plate is improved and the stress concentration to the tube width direction edge part in a tube is suppressed.

Further, as shown in FIG. 10, in the heat exchanger described in Patent Document 1, the inner side of the tank is inserted into the inner peripheral edge of the tube insertion hole J221 in the core plate J20 and the insert insertion hole J222 into which the insert is inserted. By forming the cylindrical burring portion J221a protruding to the side, the rigidity of the core plate J20 is further increased.
JP 2004-219044 A

  By the way, in the heat exchanger of the above structures, it is known that the rigidity of a core plate will become high, so that the height from the tube joint surface of a rib or a burring part is high. However, increasing the height of the ribs and burring portions and setting the ribs and burring portions within a limited range has a problem that the formability deteriorates when the core plate is formed by, for example, press working.

  An object of this invention is to provide the heat exchanger which can improve the moldability of a core plate, preventing the stress concentration to the tube width direction both ends of a tube in view of the said point.

In order to achieve the above object, in the present invention, a core portion (1) having a flat tube (10) arranged in a number of layers and provided at both ends of the tube (10) in the tube longitudinal direction (X), Heat exchange comprising a core plate (20) to which a tube (10) is joined, and a tank (2, 3) having a tank body (21) that constitutes a tank internal space together with the core plate (20). An end of the tube (10) in the tube longitudinal direction (X) is inserted into the tube insertion hole (221) of the tube joining surface (22) of the core plate (20) and joined. A cylindrical burring portion (221a) protruding to one side is formed on the inner peripheral edge of the insertion hole (221), and at least one of the inner peripheral edges of the tube insertion hole (221). To have the first feature that the cutting portion has a portion burring portion cut burring part (221a) (221a) is not formed (221b) is provided.

  Thus, by forming the burring portion (221a) at the inner peripheral edge of the tube insertion hole (221), the rigidity of the core plate (20) near the tube insertion hole (221) can be increased. Thereby, when distortion occurs in the tube (10), it is possible to prevent deformation of both end portions in the tube width direction (Z) of the tube insertion hole (221), so that the tube width direction of the tube (10) ( Z) Stress concentration at both ends can be prevented.

For example, when the burring portion (221a) is formed by press working, the burring portion (221a) is likely to be cracked. For this reason, a cutting part (221b) that is a part where the burring part (221a) is not formed by cutting a part of the burring part (221a) in advance is provided at the inner peripheral edge of the tube insertion hole (221). Thus, the occurrence of cracks can be prevented and the moldability of the core plate (20) can be improved.

  Thus, it becomes possible to improve the moldability of the core plate (20) while preventing stress concentration on both ends of the tube (10) in the tube width direction (Z).

In the present invention, the tube (10) connects a pair of straight portions (10a) whose cross sections perpendicular to the tube longitudinal direction (X) are parallel to each other and the ends of the pair of straight portions (10a). It consists of an arcuate part (10b), and the cut part (221b) is also characterized in that it is provided at a site corresponding to the arcuate part (10b) in the tube insertion hole (221).

  When the burring portion (221a) is formed by press working, cracking is most likely to occur at a portion corresponding to the arc-shaped portion (10b) of the tube (10) in the burring portion (221a). For this reason, the moldability of the core plate (20) can be further improved by providing the cut portion (221b) at a portion corresponding to the arc-shaped portion (10b) in the tube insertion hole (221).

In this case, between the cutting part (221b) and the surface (224) perpendicular to the tube longitudinal direction (X) in the core plate (20), there is an inclined part inclined with respect to the orthogonal surface (224) . it can be.

In this way, when the tube (10) is distorted, the connection point between the inclined surface and the surface (224) orthogonal to the tube longitudinal direction (X) in the core plate (20) is deformed, The deformation of the tube (10) can be absorbed by the deformation. Thereby, stress concentration to the tube width direction (Z) both ends of a tube (10) can be prevented more reliably.

In this case, when the direction perpendicular to both the tube longitudinal direction (X) and the tube lamination direction (Y) is the tube width direction (Z), the tube width direction (Z) of the tube insertion hole (221) The ratio (L2 / L1) of the projection length (L2) when the inclined portion with respect to the length (L1) is projected onto a virtual plane orthogonal to the tube longitudinal direction (X) is 0.05 or more, 0.3 The following ranges can be adopted.

  If it does in this way, the effect which prevents the stress concentration to the tube width direction (Z) both ends of the tube (10) and the effect which improves the moldability of a core plate (20) can be made to make compatible.

  Moreover, you may provide a cutting | disconnection part (221b) in the site | part corresponding to the straight part (10a) in a tube insertion hole (221).

In the present invention, the burring portion (221a) and the cutting portion (221b) are provided only in the tube insertion holes (221) disposed in the vicinity of both ends in the tube stacking direction (Y) of the core plate (20). This is a second feature.

  Generally, the tube (10) in which thermal distortion occurs due to a temperature difference between the tubes (10) tends to be biased toward both ends of the tube stacking direction (Y). For this reason, the tube of the tube (10) is formed by forming the burring portion (221b) only in the tube insertion holes (221) arranged in the vicinity of both ends of the tube stacking direction (Y) where a larger thermal strain is likely to occur. Stress concentration at both ends in the width direction (Z) can be more effectively prevented.

  Moreover, since it is not necessary to provide a burring part (221b) in the tube insertion hole (221) arrange | positioned in a tube lamination direction (Y) intermediate part, the moldability of a core plate (20) can be improved more.

Moreover, in the heat exchanger having the first to fourth features, when the tube width direction (Z) is a direction orthogonal to the tube longitudinal direction (X) and the tube stacking direction (Y), tube bonding A plurality of ribs (223) extending in the tube width direction (Z) can be formed on the surface (22).

  In this way, since the rigidity of the core plate (4) can be further increased, stress concentration on both ends of the tube (10) in the tube width direction (Z) can be prevented.

  In this case, a plurality of ribs (223) can be disposed in the vicinity of both ends of the core plate (20) in the tube stacking direction (Y).

  In this way, stress is concentrated on both ends of the tube (10) in the tube width direction (Z) by disposing the ribs (223) only in the vicinity of both ends of the tube stacking direction (Y) where larger thermal strain is likely to occur. Can be prevented more effectively. Moreover, since it is not necessary to provide the rib (223) in the tube lamination direction (Y) middle part, the moldability of the core plate (20) can be further improved.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.

Hereinafter, embodiments of the present invention will be described. The first embodiment is a reference example, and the second and subsequent embodiments are embodiments of the invention described in the claims.
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the heat exchanger according to the present invention is applied to a radiator for cooling a water-cooled internal combustion engine. FIG. 1 is a front view of a heat exchanger according to the first embodiment of the present invention, and FIG. 2 is a perspective sectional view of tanks 2 and 3 and a tube 10 in the heat exchanger of FIG.

  As shown in FIG. 1 and FIG. 2, the heat exchanger includes a rectangular parallelepiped core portion 1, and the core portion 1 has a large number of tubes 10 and a large number of corrugated fins 11 stacked alternately in the vertical direction. Configured. The stacking direction of the tube 10 and the corrugated fin 11 is hereinafter referred to as a tube stacking direction Y.

  The corrugated fins 11 are made of an aluminum alloy and are formed in a corrugated shape to promote heat exchange between air and cooling water.

  The tube 10 has a passage through which cooling water of a water-cooled internal combustion engine (not shown) mounted on the vehicle flows, and is formed by bending or welding or brazing an aluminum alloy plate material into a predetermined shape. Is done.

  In the present embodiment, the tube 10 has a flat shape in which the longitudinal direction (hereinafter referred to as the tube longitudinal direction X) coincides with the horizontal direction, and the cross-sectional shape thereof coincides with the air flow direction A. Is formed. The direction orthogonal to both the tube stacking direction Y and the tube longitudinal direction X is hereinafter referred to as a tube width direction Z. Incidentally, the tube width direction Z coincides with the major axis direction of the tube 10 and the air flow direction A. More specifically, the tube 10 includes a pair of straight portions 10a whose cross sections perpendicular to the tube longitudinal direction X are parallel to each other, and an arcuate portion 10b that connects the ends of the pair of straight portions 10a. The straight portion 10a is parallel to the tube width direction Z.

  At both ends of the tube 10 in the tube longitudinal direction X, tanks 2 and 3 extending in a direction substantially orthogonal to the tube longitudinal direction X and having a space formed therein are disposed. The ends of the tubes 10 in the longitudinal direction X of the tube 10 are inserted into and joined to the tanks 2 and 3 in tube insertion holes 221 (details will be described later). It communicates with the space.

  One tank 2 distributes and supplies the high-temperature cooling water flowing out from the engine to a number of tubes 10. The one tank 2 is provided with an inlet pipe 20 connected to the cooling water outlet side of the internal combustion engine via a hose (not shown).

  The other tank 3 collects and collects the cooling water cooled by heat exchange with air and drains it toward the internal combustion engine. The other tank 3 is provided with an outlet pipe 30 connected to the coolant inlet side of the internal combustion engine via a hose.

  Inserts 4 that reinforce the core portion 1 are disposed at both ends of the core portion 1 in the tube stacking direction Y. The insert 4 is made of an aluminum alloy, extends in a direction parallel to the tube longitudinal direction X, and both ends thereof are connected to the tanks 2 and 3. Further, the insert 4 is thicker than the tube 10.

  The tanks 2 and 3 have a core plate 20 in which the tube 10 and the insert 4 are inserted and fixed, a tank body 21 that forms a space 2a in the tanks 2 and 3 together with the core plate 20, and a packing (not shown). Configured.

  In this embodiment, the core plate 20 is made of an aluminum alloy, the tank main body 21 is made of a resin such as glass fiber reinforced nylon 66, and the rubber packing for keeping the airtightness is used as the core plate 20 and the tank main body. In a state of being sandwiched between the tank body 21 and the tank body 21, the tank body 21 is caulked and fixed to the core plate 20 by plastic deformation so as to press a protruding piece 251 of the core plate 20 to be described later against the tank body 21.

  3A is a front view of the core plate 20 alone in FIG. 2, FIG. 3B is a bottom view of FIG. 3A, and FIG. 4 is a sectional view taken along line BB in FIG.

  As shown in FIGS. 3A, 3B, and 4, the core plate 20 has a tube joining surface 22 to which the tube is joined. Around the tube joining surface 22, the end of the tank main body 21 is provided. A groove 20a having a substantially rectangular cross section into which the packing is inserted is formed over the entire circumference.

  The groove 20a is formed by three surfaces. That is, an inner wall portion 23 that is bent substantially vertically from the outer peripheral portion of the tube joining surface 22 and extends in the tube longitudinal direction X, and a bottom wall portion 24 that is bent substantially vertically from the inner wall portion 23 and extends in the tube stacking direction Y. A groove 20 a is formed by the outer wall portion 25 that is bent substantially perpendicularly from the bottom wall portion 24 and extends in the tube longitudinal direction X. A large number of protruding pieces 251 are formed at the end of the outer wall portion 25.

  A number of tube insertion holes 221 into which the tube 10 is inserted and brazed are formed along the tube stacking direction Y on the tube joint surface 22 of the core plate 20. In addition, one insert insertion hole 222 into which the insert 4 is inserted and brazed is formed on each end of the tube joining surface 22 in the tube stacking direction Y.

  At the edge of the tube insertion hole 221, a burring portion 221a formed in a cylindrical shape so as to protrude toward the inner side of the tanks 2 and 3 (outside of the tube longitudinal direction X) is formed. By providing the burring portion 221a, the rigidity around the tube insertion hole 221 in the core plate 20 can be increased. On the other hand, no burring portion is formed in the insert insertion hole 222.

  Furthermore, ribs 223 that protrude from the tube joint surface 22 to the outside of the tank are formed on the tube joint surface 22 between the adjacent tube insertion holes 221 and between the tube insertion holes 221 and the insert insertion holes 222 by, for example, pressing. Is formed.

  Each insertion hole 221, 222 and rib 223 extend long in the tube width direction Z, and the rib 223 is longer than each insertion hole 221, 222. Moreover, the tube width direction Z both ends in the rib 223 are extended to the tube width direction Z outer side rather than the tube width direction Z both ends in each insertion hole 221,222.

  Both ends of the rib 223 in the tube width direction Z do not reach the inner wall portion 23. In other words, the tube width direction Z both ends of the rib 223 are not connected to the inner wall portion 23. Therefore, a flat surface 224 exists outside the tube width direction Z both ends of the insertion holes 221 and 222 and the ribs 223 in the tube joining surface 22 and over the entire region in the tube stacking direction Y. The flat surface 224 can be easily deformed in the tube longitudinal direction X. Therefore, when the temperature difference between the tubes 10 is large, the core plate 20 is deformed in the tube longitudinal direction X by the deformation of the flat surface 224, and the deformation of the tube 10 absorbs the thermal strain of the tube 10, and the tube width in the tube 10 is increased. The stress can be reduced in the entire direction Z.

  As described above, by forming the burring portion 221a at the inner peripheral edge of the tube insertion hole 221, the rigidity of the core plate 20 near the tube insertion hole 221 can be increased. As a result, when a temperature difference occurs between the tubes 10 and thermal distortion occurs in the tubes 10, it is possible to prevent deformation of both end portions in the tube width direction Z of the tube insertion holes 221. Stress concentration at both ends in the width direction Z can be prevented.

  In addition, by forming the burring portion 221a only in the tube insertion hole 221 out of the tube insertion hole 221 and the insert insertion hole 222, it is not necessary to form a burring portion in the insert insertion hole 222. Can be improved. Since the insert 4 is thicker than the tube 10 and is hardly damaged by stress concentration, the effect of preventing stress concentration on both ends of the tube 10 in the tube width direction Z can be ensured.

  Therefore, it becomes possible to improve the moldability of the core plate 20 while preventing stress concentration at both ends of the tube 10 in the tube width direction Z.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 5 is a bottom view of the core plate 20 alone in the heat exchanger according to the second embodiment, and FIG. 6 is a cross-sectional view taken along the line CC in FIG.

  As shown in FIGS. 5 and 6, in each tube insertion hole 221, a cutting portion 221b for cutting the burring portion 221a is provided at the inner peripheral edge of the tube insertion hole 221. In other words, in each tube insertion hole 221, there is a portion where the burring portion 221a is not formed at the inner peripheral edge of the tube insertion hole 221. In this embodiment, the cutting part 221b is provided in the site | part corresponding to the circular arc-shaped part 10b of the tube 10 in the tube insertion hole 221 one each.

  When the burring part 221a is formed by press working, cracking is likely to occur in the burring part 221a. For this reason, by providing a cutting part 221b in which a part of the burring part 221a is cut in advance at the inner peripheral edge of the tube insertion hole 221, that is, by eliminating the burring part 221a, the occurrence of cracks is prevented, and the core plate 20 formability can be improved.

  Furthermore, the cracking at the time of forming the burring portion 221a is most likely to occur at a portion corresponding to the arcuate portion 10b of the tube 10. Therefore, as in the present embodiment, by providing the cutting part 221b in advance in the portion corresponding to the arcuate part 10b in the tube insertion hole 221, the occurrence of cracks can be prevented more reliably and the moldability of the core plate 20 can be improved. It can be improved further. According to the study by the present inventors, stress concentration at both ends of the tube width direction Z of the tube 10 is prevented even if the burring portion 221a corresponding to the arcuate portion 10b in the tube insertion hole 221 is eliminated. It was confirmed that the effect on the effect was small.

  Therefore, the moldability of the core plate 20 can be further improved while preventing stress concentration at both ends of the tube 10 in the tube width direction Z.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. The same parts as those in the second embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 7 is a cross-sectional view of the core plate 20 in the heat exchanger according to the third embodiment cut in the tube width direction Z, and corresponds to FIG.

As shown in FIG. 7, a cut portion 221 b (a portion where the burring portion 221 a is not formed) in the inner peripheral edge of the tube insertion hole 221 and a flat surface 224, that is, a surface orthogonal to the tube longitudinal direction X in the core plate 20. Is an inclined portion inclined with respect to the flat surface (224). Specifically, the inclined portion is inclined so as to go inward of the tanks 2 and 3 as it approaches the center of the tube insertion hole 221.

In this way, when a temperature difference occurs between the tubes 10 and thermal distortion occurs in the tubes 10, the connection point (bending point portion) D between the flat surface 224 and the inclined portion of the core plate 20 is deformed. And the thermal distortion of the tube 10 can be absorbed by the deformation | transformation. Thereby, the stress concentration to the tube width direction Z both ends of the tube 10 can be prevented more reliably.

At this time, the ratio L2 / L1 of the projection length L2 when the inclined portion of the tube insertion hole 221 with respect to the length L1 in the tube width direction Z is projected onto a virtual plane orthogonal to the tube longitudinal direction X is 0.05. As mentioned above, by setting it as the range of 0.3 or less, the effect which prevents the stress concentration to the tube width direction Z both ends of the tube 10 and the effect which improves the moldability of the core plate 20 can be made compatible.

Incidentally, if L2 / L1 is too small, it becomes difficult to form the connection point D between the flat surface 224 and the inclined portion of the core plate 20, and when the tube 10 is thermally strained, the connection point D is deformed. It becomes difficult to absorb the thermal strain of the tube 10. On the other hand, if L2 / L1 is too large, the distance between the tube width direction Z end of the tube 10 and the connection point D becomes long, and the thermal strain of the tube 10 cannot be absorbed.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the second embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 8 is a bottom view of the core plate 20 alone in the heat exchanger according to the fourth embodiment.

  As shown in FIG. 8, one cutting portion 221 b is provided at a portion corresponding to the straight portion 10 a of the tube 10 in the tube insertion hole 221. Moreover, the cutting part 221b is provided in the same site | part in each tube insertion hole 221. FIG. Thereby, generation | occurrence | production of the crack at the time of burring part 221a formation can be prevented, and the moldability of the core plate 20 can be improved.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to FIG. The same parts as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 9 is a bottom view of the core plate 20 alone in the heat exchanger according to the fifth embodiment.

  As shown in FIG. 9, the burring portion 221 a is provided only in the tube insertion holes 221 disposed in the vicinity of both ends of the core plate 20 in the tube stacking direction Y. The ribs 223 are also disposed in the vicinity of both ends of the core plate 20 in the tube stacking direction Y. In the present embodiment, the burring part 221a is provided in the tube insertion hole 221 from the end part in the tube stacking direction Y in the core plate 20 to the third. The ribs 223 are arranged between the adjacent tube insertion holes 221 from the end of the core plate 20 in the tube stacking direction Y to the third, and between the tube insertion holes 221 and the insert insertion holes 222.

  Generally, the tube 10 in which thermal strain is generated due to a temperature difference between the tubes 10 tends to be biased toward both ends of the tube stacking direction Y. For this reason, the burring portion 221b is formed only in the tube insertion holes 221 disposed in the vicinity of both ends of the tube stacking direction Y where a larger thermal strain is likely to occur, and the rib 223 is formed only in the vicinity of both ends of the tube stacking direction Y. Thereby, the stress concentration to the tube width direction Z both ends of the tube 10 can be prevented more effectively.

  Further, it is not necessary to provide the burring portion 221b in the tube insertion hole 221 disposed in the middle portion of the tube stacking direction Y, and it is not necessary to provide the rib 223 in the middle portion of the tube stacking direction Y. Can be improved.

  Incidentally, “in the vicinity of the end of the core plate 20 in the tube stacking direction Y” means that, in the case of a generally used radiator having a total number of tubes 10 of 30 or more, the tube starts from the end of the core plate 20 in the tube stacking direction Y A range in which 3 to 5 insertion holes 221 are arranged.

(Other embodiments)
In each of the above embodiments, the rib 223 is provided on the tube joining surface 22 of the core plate 20, but it may not be provided.

  Moreover, in the said 2nd-4th embodiment, although the burring part is not provided in the inner peripheral part of the insert insertion hole 222, you may provide.

  Further, in the third embodiment, the cutting part 221b is inclined so as to go inward of the tanks 2 and 3 as it approaches the center of the tube insertion hole 221, but the tank approaches the center of the tube insertion hole 221. You may make it incline so that it may go a few outwards. In this case, the burring portion 221b protrudes toward the outer side of the tanks 2 and 3, and the rib 223 protrudes from the tube joint surface 22 to the inside of the tank.

  In the fourth embodiment, one cutting part 221b is provided in each tube insertion hole 221, but two or more cutting parts may be provided.

  Moreover, in the said 5th Embodiment, although the cutting part 221b is not provided in the burring part 221a of the tube insertion hole 221, you may provide the cutting part 221b. In this case, a burring portion may be provided on the inner peripheral edge of the insert insertion hole 222. Moreover, when the cutting part 221b is provided in the part corresponding to the arcuate part 10b of the tube 10 in the tube insertion hole 221, the cutting part 221b may be inclined with respect to the flat surface 224.

  In addition, the configuration of each of the above embodiments concentrates stress on both ends of the tube width direction Z of the tube 10 not only for thermal strain but also for strain of the tube 10 due to changes in internal pressure, vehicle vibration, and the like. Demonstrate the effect.

It is a front view of the heat exchanger which concerns on 1st Embodiment. FIG. 2 is a perspective sectional view of tanks 2 and 3 and a tube 10 in the heat exchanger of FIG. 1. (A) is a front view of the core plate 20 alone in FIG. 2, and (b) is a bottom view of (a). It is BB sectional drawing of FIG.3 (b). It is a bottom view of the core plate 20 single-piece | unit in the heat exchanger which concerns on 2nd Embodiment. It is CC sectional drawing of FIG. It is sectional drawing which cut | disconnected the core plate 20 in the tube width direction Z in the heat exchanger which concerns on 3rd Embodiment. It is a bottom view of the core plate 20 single-piece | unit in the heat exchanger which concerns on 4th Embodiment. It is a bottom view of the core plate 20 single-piece | unit in the heat exchanger which concerns on 5th Embodiment. It is sectional drawing which cut | disconnected the core plate J20 in the conventional heat exchanger in the tube lamination direction.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Core part, 2, 3 ... Tank, 4 ... Insert, 10 ... Tube, 20 ... Core plate, 21 ... Tank main-body part, 22 ... Tube joint surface, 221 ... Tube insertion hole, 221a ... Burring part, 221b ... Cutting Part, 222 ... insert insertion hole, 223 ... rib.

Claims (6)

A core portion (1) having a flat tube (10) arranged in a number of layers;
A core plate (20) that is provided at both ends of the tube (10) in the tube longitudinal direction (X) and to which the tube (10) is joined, and a tank body that constitutes a tank internal space together with the core plate (20) A heat exchanger comprising a tank (2, 3) having a portion (21),
The tube (10) includes a pair of straight portions (10a) whose cross sections perpendicular to the tube longitudinal direction (X) are parallel to each other, and an arcuate portion that connects the ends of the pair of straight portions (10a) ( 10b)
The tube longitudinal direction (X) end of the tube (10) is joined by being inserted into a tube insertion hole (221) of a tube joining surface (22) of the core plate (20),
A cylindrical burring part (221a) protruding to one side is formed on the inner peripheral edge of the tube insertion hole (221),
At least one of the inner peripheral edges of the tube insertion hole (221) is a cut portion (221b) that is a portion where the burring portion (221a) is not formed by cutting the burring portion (221a). Is provided ,
The cutting part (221b) is provided at a site corresponding to the arcuate part (10b) in the tube insertion hole (221),
Between the cutting part (221b) and the surface (224) perpendicular to the tube longitudinal direction (X) in the core plate (20) is an inclined part that is inclined with respect to the orthogonal surface (224). heat exchanger, characterized in that is. When the direction perpendicular to both the tube longitudinal direction (X) and the tube stacking direction (Y) is the tube width direction (Z),
Projected length (L2) when the inclined portion with respect to the length (L1) in the tube width direction (Z) of the tube insertion hole (221) is projected onto a virtual plane orthogonal to the tube longitudinal direction (X). The heat exchanger according to claim 1 , wherein the ratio (L2 / L1) is in a range of 0.05 to 0.3. A core portion (1) having a flat tube (10) arranged in a number of layers;
A core plate (20) that is provided at both ends of the tube (10) in the tube longitudinal direction (X) and to which the tube (10) is joined, and a tank body that constitutes a tank internal space together with the core plate (20) A heat exchanger comprising a tank (2, 3) having a portion (21),
The tube (10) includes a pair of straight portions (10a) whose cross sections perpendicular to the tube longitudinal direction (X) are parallel to each other, and an arcuate portion that connects the ends of the pair of straight portions (10a) ( 10b)
The tube longitudinal direction (X) end of the tube (10) is joined by being inserted into a tube insertion hole (221) of a tube joining surface (22) of the core plate (20),
A cylindrical burring part (221a) protruding to one side is formed on the inner peripheral edge of the tube insertion hole (221),
At least one of the inner peripheral edges of the tube insertion hole (221) is a cut portion (221b) that is a portion where the burring portion (221a) is not formed by cutting the burring portion (221a). Is provided ,
The said cut | disconnecting part (221b) is provided in the site | part corresponding to the said straight part (10a) in the said tube insertion hole (221), The heat exchanger characterized by the above-mentioned . The burring part (221a) and the cutting part (221b) are provided only in the tube insertion hole (221) arranged in the vicinity of both ends in the tube stacking direction (Y) of the core plate (20). The heat exchanger according to any one of claims 1 to 3 , wherein When the direction perpendicular to both the tube longitudinal direction (X) and the tube stacking direction (Y) is the tube width direction (Z),
The heat exchanger according to any one of claims 1 to 4, wherein a plurality of ribs (223) extending in a tube width direction (Z) are formed on the tube joining surface (22). The heat exchanger according to claim 5 , wherein the plurality of ribs (223) are arranged in the vicinity of both ends of the core plate (20) in the tube stacking direction (Y).

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