JP2016109358A - Heat exchanger and heat exchanger manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger and a heat exchanger manufacturing method capable of suppressing a drift current of a fluid to be cooled to protect the heat exchanger from being damaged while ensuring a configuration that enables size reduction and has high reliability.SOLUTION: A plurality of tubes 21 each has a first tube 211 having an upstream end portion 211a, 212a inserted into a through-hole 331, 332 of a core plate 33 of a distribution tank part 30 and disposed near a cooling water inlet port 31a, and a second tube 212 located to be farther from the cooling water inlet port 31a than the first tube 211. A flow passage cross-sectional area of the upstream end portion of the first tube 211 is smaller than a flow passage cross-sectional area of that of the second tube 212.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a heat exchanger for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside, and a manufacturing method thereof.

  A technology for cooling and maintaining an appropriate temperature by circulating cooling water through a device that becomes hot during operation of a vehicle, such as an internal combustion engine or a turbine, is widely used. Since the cooling water becomes high temperature by exchanging heat with an internal combustion engine or the like, in order to use the cooling water again for cooling, it is necessary to dissipate heat and lower the temperature. For this reason, it is common to mount a heat exchanger that performs heat exchange between the cooling water that has become high temperature and the air that the vehicle takes in.

  The following Patent Document 1 describes a heat exchanger that allows cooling water, which is a fluid to be cooled, to flow through a plurality of tubes. In this heat exchanger, one end of each of the plurality of tubes is connected to a distribution tank unit (tank). The high-temperature cooling water supplied to the distribution tank unit is distributed to one end of each tube, and is cooled by flowing each tube from one end to the other end.

  In such a heat exchanger, the easiness of inflow of cooling water varies from tube to tube, and the cooling water tends to flow in a specific tube. This drift also causes temperature variations, such that a tube with a large flow rate of cooling water has a relatively high temperature, while a tube with a small flow rate has a relatively low temperature. For this reason, in the tube arrange | positioned in the position where a temperature difference is large, there existed a possibility that distortion might arise by the difference in the amount of thermal expansion, and it might be damaged.

  In order to solve such a problem, Patent Document 1 below discloses that a stiffener (insert member) is used to protect a tube from breakage due to distortion. Specifically, a stiffener that is a separate member from the tube and the distribution tank is used, and this stiffener is inserted into one end of the tube inside the distribution tank. Thereby, the said tube is reinforced and distortion is suppressed and breakage is prevented.

JP 2005-221127 A

  In the heat exchanger described in Patent Document 1, a stiffener is provided so as to protrude from one end of the tube into the distribution tank. For this reason, the stiffener becomes a resistance against the cooling water flow inside the distribution tank unit, and there is a possibility that the cooling water is not properly distributed to each tube. Further, in recent years, heat exchangers have been required to be further downsized, but securing a space for providing a stiffener inside the distribution tank portion has been in conflict with that requirement.

  The stiffener is fixed by being inserted into one end of the tube. For this reason, the stiffener has fallen from the tube with the long-term use of the heat exchanger, and the performance cannot be maintained. Such a stiffener may be fixed by brazing. However, even in this case, a step of brazing and a step of temporarily fixing the stiffener to the tube before brazing are required, which may increase manufacturing costs. There is.

  The present invention has been made in view of such a problem, and an object of the present invention is to prevent the breakage of the fluid to be cooled by suppressing the drift of the fluid to be cooled while the structure can be downsized and has high reliability. It is providing the manufacturing method of a heat exchanger and a heat exchanger.

  In order to solve the above problems, a heat exchanger according to the present invention is a heat exchanger (10) for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside, the fluid being cooled. A plurality of tubes (21) having tube flow paths (211f, 212f) for flowing a fluid, a cooled fluid inlet (31a) for allowing the fluid to be cooled to flow into the interior, and a target flowed from the cooled fluid inlet. And a distribution channel (32) through which the cooling fluid flows, connected to the upstream ends (211a, 212a) of the plurality of tubes, and the fluid to be cooled flows into the upstream ends of the plurality of tubes from the distribution channel A distribution tank section (30) that distributes the liquid to be cooled, and a collection tank section (40) that is connected to the downstream ends of the plurality of tubes and collects the fluid to be cooled that has flowed out of the downstream ends. The plurality of tubes have upstream end portions inserted into the through holes (331, 332) of the core plate (33) of the distribution tank portion, and the first tube (211) in the vicinity of the cooled fluid inlet, A second tube (212) positioned farther from the cooled fluid inflow port than the one tube, and the flow passage cross-sectional area of the upstream end of the first tube is larger than the flow passage cross-sectional area of the second tube small.

  When a configuration is adopted in which the cooled fluid flows from the cooled fluid inlet into the distribution tank and is distributed so as to flow into the upstream end of each tube, the cooled fluid is in the vicinity of the cooled fluid inlet. Strongly oriented to the tube. That is, among the plurality of tubes, the flow rate of the fluid to be cooled flowing into the first tube in the vicinity of the fluid inlet for cooling is such that the flow rate of the fluid flowing into the second tube located farther from the fluid inlet than the first tube. It tends to be larger than the flow rate of the cooling fluid.

  Therefore, in the present invention, the flow path cross-sectional area of the upstream end portion of the first tube is smaller than the flow path cross-sectional area of the second tube. Therefore, it is possible to prevent breakage by suppressing the drift of the fluid to be cooled to the second tube.

  In order to solve the above-mentioned problem, a method of manufacturing a heat exchanger according to the present invention includes a plurality of tubes (21) through which a fluid to be cooled flows, and a fluid inlet to be cooled that allows the fluid to be cooled to flow inside. A distribution tank section (30) having a tank (34) in which (31a) is formed and a core plate (33) to which upstream ends of the plurality of tubes (21) are connected; Of the tubes, the first tube (211) is arranged in the vicinity of the cooled fluid inlet (31a), and the second tube (212) of the plurality of tubes is further away from the cooled fluid inlet than the first tube (211). A heat exchanger (10) for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside, wherein a plurality of through-holes ( 331, 332) forming the first work A second step of forming an annular portion (331a) projecting toward the distribution flow path (32) inside the distribution tank at the edge of each through-hole, and a tube flow path (211f for flowing the fluid to be cooled) , 212f) having a plurality of tubes (21) having an upstream end (211a, 212a) inserted into each of the through holes, a third step of reducing the diameter at the upstream end of the first tube, And a fourth step of making the channel cross-sectional area of the first tube smaller than the channel cross-sectional area of the second tube.

  In the present invention, in the fourth step, the diameter is reduced at the upstream end of the first tube, and the flow passage cross-sectional area of the first tube is made smaller than the flow passage cross-sectional area of the second tube. Therefore, it is possible to prevent breakage by suppressing the drift of the fluid to be cooled to the second tube.

  Moreover, in order to solve the said subject, the manufacturing method of the heat exchanger which concerns on this invention manufactures the heat exchanger (10) which performs heat exchange between the fluid which flows outside, and the to-be-cooled fluid which flows inside. In the method, a plurality of through-holes (331) are formed in a core plate (33) of a distribution tank section (30) having a cooled fluid inlet (31a) and a distribution channel (32) through which a fluid to be cooled flows. , 332) in the first step of forming a reduced diameter portion (331b) in the through hole (331) in the vicinity of the fluid inlet for cooling to reduce the diameter from the outside to the inside of the distribution tank portion. One step and a second step of inserting a plurality of tubes (21) having tube flow paths (211f, 212f) for flowing a fluid to be cooled into each of the through holes at their upstream ends (211a, 212a). And the fluid to be cooled The upstream end (211a) of the tube (211) to be inserted into the through hole near the inlet is compressed by bringing it into contact with the reduced diameter portion as it is inserted into the through hole. And a second step of forming a tapered portion (211c) whose diameter increases toward the center of the tube channel in the flow direction of the fluid to be cooled.

  In the present invention, in the first step, the through hole in the vicinity of the fluid inlet for cooling is formed to have a reduced diameter. In the second step, by inserting the upstream end of the tube, the tube is brought into contact with the reduced diameter portion and compressed to form a tapered portion. Therefore, the upstream end of the tube can be inserted and the tapered portion can be formed at the same time, and the drift of the fluid to be cooled to the tube in the vicinity of the fluid inlet can be suppressed even with a simple manufacturing process. It becomes possible.

  According to the present invention, it is possible to provide a heat exchanger and a heat exchanger manufacturing method capable of preventing the breakage by suppressing the drift of the fluid to be cooled while reducing the size and providing a highly reliable configuration. Can do.

It is a front view which shows the heat exchanger which concerns on embodiment of this invention. It is a top view which shows the heat exchanger which concerns on embodiment of this invention. It is sectional drawing which shows the III-III cross section of FIG. It is sectional drawing which shows the IV-IV cross section of FIG. It is sectional drawing explaining the manufacturing method of the heat exchanger which concerns on 1st Embodiment of this invention. It is a figure which shows the temperature distribution in the heat exchanger which concerns on embodiment of this invention. It is a figure which shows the temperature distribution in the heat exchanger which concerns on a comparative example. It is sectional drawing explaining the manufacturing method of the heat exchanger which concerns on 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  First, the configuration of the heat exchanger 10 will be described with reference to FIGS. 1 to 4. The heat exchanger 10 is a radiator that cools cooling water that is circulated through an internal combustion engine (not shown) of the vehicle.

  The heat exchanger 10 includes a heat exchange core unit 20, a distribution tank unit 30, and a collective tank unit 40.

  The heat exchange core unit 20 is configured by a stacked body in which a plurality of tubes 21 and a plurality of fins 22 are alternately stacked in the vertical direction. In FIG. 4, illustration of the plurality of fins 22 is omitted.

  The plurality of tubes 21 include a tube 211 in the vicinity of a cooling water inlet 31 a described later, and a tube 212 positioned farther from the cooling water inlet 31 a than the tube 211. Each of the tubes 211 and 212 is a tubular member made of aluminum having a flat cross section and extending in a substantially horizontal direction. As shown in FIG. 4, the tubes 211 and 212 have tube channels 211f and 212f formed therein for flowing cooling water.

  The fin 22 is a corrugated fin and is formed by bending an aluminum plate. The fins 22 are disposed between the adjacent tubes 21 and are joined to the flat surface of the outer surface of the tubes 21.

  Side plates 23 are disposed at both ends in the stacking direction (hereinafter, this direction is also simply referred to as “stacking direction”) of the stack composed of the plurality of tubes 21 and the plurality of fins 22, and the heat exchange core section 20. Is reinforced. As indicated by an arrow X in FIG. 2, the heat exchange core portion 20 is configured such that air enters in a direction orthogonal to the stacking direction and passes between the plurality of tubes 21 and the plurality of fins 22. .

  The distribution tank unit 30 is disposed on the side of the heat exchange core unit 20. The distribution tank unit 30 includes a tank 34 in which a cooling water inlet 31 a for allowing cooling water to flow therein is formed, and a core plate 33 assembled to the tank 34, and a distribution flow for flowing cooling water into the tank 30. A path 32 is formed. A cooling water inflow pipe 31 having a flow path inside is connected to a cooling water inlet 31 a which is an opening communicating with the distribution flow path 32.

  As shown in FIG. 4, the core plate 33 has a plurality of through holes 331 and 332. The through holes 331 and 332 are linearly arranged along the stacking direction with a space between each other. Further, the upstream end portions 211a and 212a of the plurality of tubes 21 are inserted and connected to the through holes 331 and 332, respectively. The plurality of tubes 21 are configured to communicate with the distribution flow path 32 of the distribution tank unit 30.

  The collective tank unit 40 is disposed on the side of the heat exchange core unit 20 and at a position facing the distribution tank unit 30 with the heat exchange core unit 20 interposed therebetween. The collective tank unit 40 includes a tank 44 in which a cooling water discharge port 41 a for allowing cooling water to flow out to the outside is formed, and a core plate 43 assembled to the tank 44. A collecting channel (not shown) for flowing cooling water is formed inside the collecting tank portion 40. A tubular cooling water discharge pipe 41 having a flow path inside is connected to a cooling water discharge port 41a which is an opening communicating with the collective flow path.

  A plurality of through holes (not shown) are formed in the core plate 43. Downstream end portions of the plurality of tubes 21 are inserted into and joined to the through holes. The plurality of tubes 21 are configured to communicate with the collective flow path of the collective tank unit 40.

  Next, the flow of the cooling water in the heat exchanger 10 configured as described above and the cooling of the cooling water will be described.

  Cooling water that has reached a high temperature after completing heat exchange with the internal combustion engine of the vehicle is supplied to the heat exchanger 10 from the cooling water inflow pipe 31. The cooling water flows into the distribution channel 32 of the distribution tank unit 30 from the cooling water inlet 31a. The cooling water flowing through the distribution flow path 32 of the distribution tank unit 30 is distributed so as to flow into the upstream end portions 211a and 212a of the tubes 211 and 212.

  The distributed cooling water flows through the tube flow paths 211f and 212f toward the collecting tank unit 40. At this time, the cooling water exchanges heat with the air passing through the heat exchange core 20 and the tube walls of the tubes 211 and 212 and the fins 22. Thereby, the said cooling water discharge | releases heat and the temperature falls.

  The cooling water that has finished flowing through the tube flow paths 211f and 212f flows out from the downstream end portions thereof, and merges in the collective flow path of the collective tank section 40. The cooling water is discharged from the cooling water discharge port 41a to the cooling water discharge pipe 41, supplied again to the internal combustion engine of the vehicle, and used for cooling.

  Subsequently, a connection structure between the plurality of tubes 21 and the distribution tank unit 30 will be described in detail with reference to FIGS. 3 and 4.

  As described above, the plurality of tubes 21 includes two types of tubes, that is, a tube 211 and a tube 212. Four tubes 211 are arranged in the vicinity of the cooling water inlet 31 a (not shown in FIGS. 3 and 4), and the other tubes 21 are tubes 212. The upstream end portion 211a of the tube 211 has a smaller channel cross-sectional area than the other portions of the tube 211, and the tapered portion 211c decreases in diameter toward the upstream side in the cooling water flow direction of the tube channel 211f. Is formed. Therefore, it is possible to secure a sufficient flow path cross-sectional area at the center of the cooling water flow direction of the tube 211 and reduce the flow path cross-sectional area of the upstream end 211a while maintaining the performance as a heat exchanger. Yes.

  The tapered portion 211c is formed so as to be a single space in which the inside is not partitioned. In other words, at least the inside of the tapered portion 211 of the tube 211 is not provided with an inner pillar or the like for reinforcement.

  Further, the tapered portion 211 c is inserted into a plurality of through holes 331 formed in the core plate 33 of the distribution tank portion 30. The through hole 331 is elliptical and penetrates the core plate 33.

  As shown in FIG. 4, the through hole 331 has an annular portion 331 a that protrudes toward the distribution channel 32 at the edge thereof. The annular portion 331 a is formed with a reduced diameter portion 331 b that decreases in diameter from the outside to the inside of the distribution tank portion 30. The reduced diameter portion 331b is in contact with the outer surface of the tapered portion 211c, and both are fixed to each other by brazing.

  In general, a tube provided in the vicinity of the cooling water inlet 31a tends to allow the cooling water to flow more easily than a tube positioned away from the cooling water inlet. As described above, the cooling water is biased to flow in a specific tube, which may cause temperature variation for each tube, distortion due to a difference in thermal expansion amount, and damage due to the distortion.

  On the other hand, in the heat exchanger 10, the flow path cross-sectional area of the tapered portion 211 c of the tube 211 is smaller than the flow path cross-sectional area of the upstream end portion 212 a of the tube 212. Thereby, the flow resistance when the cooling water of the distribution flow path 32 flows into the tube 211 can be increased, and the directivity of the cooling water to the tube 212 can be increased. As a result, the bias of the cooling water to the tube 211 can be suppressed, and the flow rate of the cooling water can be made uniform between the tube 211 and the tube 212. Therefore, it is possible to suppress the occurrence of distortion due to the drift of the cooling water and protect it from breakage.

  Then, the manufacturing method of the heat exchanger 10 which concerns on 1st Embodiment of this invention is demonstrated, referring FIG. In detail, the connection method of the some tube 21 and the distribution tank part 30 is demonstrated. FIG. 5 is a cross-sectional view corresponding to FIG.

  First, through holes 331 and 332 are formed by performing burring processing on the flat core plate 33. FIG. 5A shows the core plate 33 after burring. The through holes 331 and 332 formed in this step have the same shape, and the reduced diameter portion 331b described above is not yet formed in the through hole 331.

  In the next step, as shown in FIG. 5B, the upstream end 211 a of the tube 211 is inserted into the through hole 331 and the upstream end 212 a of the tube 212 is inserted into the through hole 332.

In the next step, as shown in FIG. 5B, the annular portion 331 a is compressed from the outer peripheral side together with the upstream end portion 211 a of the tube 211 inserted into the through hole 331. Thereby, the annular portion 331a and the upstream end portion 211a are plastically deformed inward, and as shown in FIG. 5C, a tapered portion 211c is formed at the upstream end portion 211a. As described above, the inner portion of the taper portion 211 is not provided with a reinforcing inner pillar or the like, and is formed to be a single space that is not partitioned. Therefore, deformation of the upstream end 211a is relatively easy.
Subsequently, the tubes 211 and 212 are cored by brazing between the upstream end portion 211a and the annular portion 331a of the through hole 331 and between the upstream end portion 212a and the annular portion 332a of the through hole 332. Fix to the plate 33.

  According to the manufacturing method as described above, the cooling water to the tube in the vicinity of the cooling water inlet 31a is suppressed while suppressing the formation of a gap between the annular portion 331a and the tapered portion 211c to improve water tightness. It is possible to suppress the current drift.

  Subsequently, the temperature distribution in the heat exchanger 10 configured and manufactured as described above and the heat exchanger 10A according to the comparative example will be described with reference to FIGS. 6 and 7. 6 and 7 are front views of the heat exchangers 10 and 10A, respectively, and the illustration of the tube 21 and the like is omitted.

  The heat exchanger 10A according to the comparative example is different from the heat exchanger 10 according to the present invention in the configuration of the heat exchange core portion 20A. In detail, the tube 212 is employ | adopted as the tube 21 which comprises the heat exchange core part 20A of 10 A of heat exchangers. That is, in the heat exchanger 10A, the flow path cross-sectional areas of the upstream end portions of the tubes 21 constituting the heat exchange core portion 20A are all the same. Below, about the structure which has the same function as the heat exchanger 10 among heat exchanger 10A, the same code | symbol is attached | subjected and description is abbreviate | omitted suitably.

  In the heat exchangers 10 and 10A, the cooling water of about 80 ° C. flows into the distribution tank unit 30 from the cooling water inlet 31a. The cooling water is distributed from the distribution tank unit 30 to each tube 21 of the heat exchange core unit 20, and the temperature gradually increases as each tube 21 flows from the distribution tank unit 30 side toward the collecting tank unit 40 side. descend.

  As shown in FIG. 7, in the heat exchanger 10A according to the comparative example, it can be seen that the temperature in the vicinity of the cooling water inlet 31a is extremely higher than the surroundings. That is, since the high-temperature cooling water that has flowed into the distribution flow path 32 of the distribution tank unit 30 from the cooling water inlet 31a tends to flow toward the tubes 21 in the vicinity of the cooling water inlet 31a, this position is compared to other positions. Tend to be hot.

  For this reason, the tube 21 constituting the heat exchange core portion 20A of the heat exchanger 10A has a difference in thermal expansion between the vicinity of the cooling water inlet 31a and the vicinity thereof, and there is a possibility that distortion may occur and breakage. This tends to be noticeable in the connection portion between the downstream end portion of the tube 21 and the collecting tank portion 40.

On the other hand, in the heat exchanger 10 according to the present invention, as shown in FIG. 6, it can be seen that the temperature rise in the vicinity of the cooling water inlet 31a is suppressed. That is, as mentioned above,
It can be seen that in the tube 211 in the vicinity of the cooling water inlet 31a, the flow passage cross-sectional area of the tapered portion 211c is made smaller than that of the tube 212, thereby suppressing the uneven flow of the cooling water to the tube 211.

  For this reason, in the tube 21 which comprises the heat exchange core part 20 of the heat exchanger 10, the difference of the thermal expansion amount which arises in the cooling water inflow port 31a vicinity and its periphery can be suppressed. Therefore, it becomes possible to protect the heat exchanger 10 from the distortion resulting from the difference in the amount of thermal expansion and damage.

  Next, a method for manufacturing the heat exchanger 10 according to the second embodiment of the present invention will be described with reference to FIG. In detail, the connection method of the some tube 21 and the distribution tank part 30 is demonstrated. FIG. 8 is a cross-sectional view corresponding to FIG.

  First, through holes 331 and 332 are formed by performing burring processing on the flat core plate 33. FIG. 8A shows the core plate 33 after burring. A through-hole 331 formed in the vicinity of the cooling water inlet 31a (not shown in FIG. 8) in this step has a reduced diameter portion 331b formed in advance.

  In the next step, as shown in FIG. 8B, the upstream end 211 a of the tube 211 is inserted into the through hole 331 and the upstream end 212 a of the tube 212 is inserted into the through hole 332. At this time, the upstream end portion 211a of the tube 211 is in contact with the reduced diameter portion 331b of the through hole 331, and receives a force so as to be compressed inward from the reduced diameter portion 331b along with the insertion. As a result, the upstream end 211a of the tube 211 is plastically deformed inward. Further, the tubes 211 and 212 are connected to the core plate by brazing between the upstream end portion 211a and the annular portion 331a of the through hole 331 and between the upstream end portion 212a and the annular portion 332a of the through hole 332. 33 is fixed.

  By further inserting the tubes 211 and 212 into the through holes 331 and 332, as shown in FIG. 8C, a tapered portion 211c is formed at the upstream end portion 211a of the tube 211. Thereby, the flow path cross-sectional area of the upstream end portion 211 a of the tube 211 can be made smaller than the flow path cross-sectional area of the upstream end portion 212 a of the tube 212.

  According to the manufacturing method as described above, it is possible to simultaneously insert the upstream end portion 211a of the tube 211 and form the tapered portion 211c. Therefore, it is possible to suppress the drift of the cooling water to the tube 211 in the vicinity of the cooling water inlet 31a while simplifying the manufacturing process.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Heat exchanger 21: Tube 30: Distribution tank unit 31a: Cooling water inlet (cooled fluid inlet)
32: Distribution channel 33: Core plate 40: Collecting tank unit 211: Tube (first tube)
211a, 212a: upstream end 211c: taper 211f, 212f: tube flow path 212: tube (second tube)
331, 332: through holes 331a, 332a: annular portion 331b: reduced diameter portion

Claims (8)

A heat exchanger (10) for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside,
A plurality of tubes (21) having tube flow paths (211f, 212f) for flowing a fluid to be cooled inside;
A cooled fluid inlet (31a) for allowing the fluid to be cooled to flow therein; and a distribution channel (32) for flowing the cooled fluid flowing from the cooled fluid inlet; upstream of the plurality of tubes A distribution tank section (30) connected to the end sections (211a, 212a) and distributing the cooled fluid so as to flow into the upstream end sections of the plurality of tubes from the distribution flow path;
A collecting tank (40) connected to the downstream ends of the plurality of tubes and collecting the fluid to be cooled that has flowed out of the downstream ends,
The plurality of tubes have upstream end portions inserted into the through holes (331, 332) of the core plate (33) of the distribution tank portion, and the first tube (211) in the vicinity of the cooled fluid inlet. And a second tube (212) located farther from the cooled fluid inlet than the first tube,
The heat exchanger according to claim 1, wherein a flow path cross-sectional area of an upstream end of the first tube is smaller than a flow path cross-sectional area of the second tube.   2. The heat exchanger according to claim 1, wherein the first tube has a tapered portion (211 c) that is reduced in diameter toward the distribution flow path side at the upstream end portion.   3. The heat exchange according to claim 2, wherein the core plate has an annular portion (331 a) that protrudes toward the distribution channel and contacts the outer surface of the tapered portion at an edge of the through hole. vessel.   4. The heat exchanger according to claim 2, wherein the tapered portion is formed so as to be a single space in which the inside is not partitioned. 5. A plurality of tubes (21) through which the fluid to be cooled flows;
A tank (34) having a cooled fluid inlet (31a) through which the fluid to be cooled flows is formed, and a core plate (33) to which upstream ends of the plurality of tubes (21) are connected. A distribution tank section (30),
Of the plurality of tubes, a first tube (211) is disposed in the vicinity of the fluid inlet (31a), and among the plurality of tubes, the second tube (212) is more than the first tube (211). It is arranged away from the cooled fluid inlet,
A method for producing a heat exchanger (10) for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside,
A first step of forming a plurality of through holes (331, 332) in the core plate of the distribution tank section;
A second step of forming an annular portion (331a) projecting toward the distribution flow path (32) inside the distribution tank at the edge of each through hole;
A third step of inserting upstream end portions (211a, 212a) of a plurality of tubes (21) having tube flow paths (211f, 212f) for flowing a fluid to be cooled into each of the through holes;
And a fourth step of reducing the diameter at the upstream end of the first tube and making the flow path cross-sectional area of the first tube smaller than the flow path cross-sectional area of the second tube. Manufacturing method of heat exchanger.   In the fourth step, by compressing the upstream end portion of the tube inserted into the through hole from the outer peripheral side, the tube channel is compressed toward the upstream end portion side in the flow direction of the fluid to be cooled. The method for manufacturing a heat exchanger according to claim 5, wherein a taper portion (211c) having a diameter is formed at the upstream end portion.   The heat exchange according to claim 5 or 6, wherein in the fourth step, the annular portion formed at an edge portion of the through-hole into which the first tube is inserted is compressed from the outer peripheral side. Manufacturing method. A method for producing a heat exchanger (10) for exchanging heat between a fluid flowing outside and a fluid to be cooled flowing inside,
A plurality of through holes (331, 332) are formed in the core plate (33) of the distribution tank portion (30) having the cooled fluid inlet (31a) and the distribution flow path (32) through which the cooled fluid flows. The first step is to form a reduced diameter portion (331b) that decreases in diameter from the outside to the inside of the distribution tank portion in the through hole (331) in the vicinity of the fluid inlet for cooling. Process,
A second step of inserting a plurality of tubes (21) having tube flow paths (211f, 212f) for flowing a fluid to be cooled into each of the through holes at their upstream ends (211a, 212a); The upstream end (211a) of the tube (211) to be inserted into the through hole in the vicinity of the fluid inlet for cooling is brought into contact with the reduced diameter portion and compressed as the tube is inserted into the through hole. Then, the 2nd process of forming the taper part (211c) diameter-expanded toward the to-be-cooled fluid flow direction center part of the said tube flow path in this upstream end part, The manufacturing method of a heat exchanger.

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