JP2019090573A - Heat exchanger and manufacturing method of the same - Google Patents

Abstract

To provide a heat exchanger which can surely alleviate stress concentration in a tube root portion while improving moldability of a core plate, and to provide a manufacturing method of the same.SOLUTION: A cross section orthogonal to the longer direction in a tube 2 includes: a pair of linear parts 21 parallel with each other; and a bent part 22 for connecting end parts of the pair of linear parts 21 with each other, and bent so as to protrude toward the outside in the longer direction. The end part in the longer direction in the tube 2 is joined in a state of being inserted in a tube insertion hole 511a of a tube joint surface 511 in a core plate 51. In an inner peripheral edge part of the tube insertion hole 511a, a cylindrical burring part 53 protruding to one side is formed. Out of the inner peripheral part of the tube insertion hole 511a, at each of the portions corresponding to the pair of linear parts 21, at least one cut part 54 is provided which is a portion where the burring part 53 is cut off and the burring part 53 is not formed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat exchanger and a method of manufacturing the same.

  A heat exchanger such as a radiator includes a core portion in which a plurality of tubes and a plurality of corrugated fins are alternately stacked, a header tank joined to a longitudinal end of the tubes, and in communication with the tubes. The header tank has a core plate that is brazed and joined with the tubes inserted.

  In this type of heat exchanger, when a high-temperature heat transfer medium flows inside the tube, the heat of the heat transfer medium heats the tube to generate elongation. At this time, if the difference in elongation occurs between the plurality of tubes, the free expansion and contraction between the plurality of tubes is inhibited, and stress is generated at the joint between the core plate and the tube (hereinafter referred to as a rooted portion) .

  Moreover, in this type of heat exchanger, a flat tube having a flat cross-sectional shape is adopted as the tube. The cross section perpendicular to the longitudinal direction of the flat tube is configured to have a pair of linear portions parallel to each other and a curved portion connecting the ends of the pair of linear portions. In such a tube, when stress is generated in the rooted portion as described above, the stress is concentrated in the vicinity of the curved portion which is the end portion in the width direction of the tube (that is, the flow direction of the external fluid).

  On the other hand, in Patent Document 1, heat exchange is performed to disperse stress generated in the rooted portion by providing a cylindrical burring portion protruding to one side at the inner peripheral edge portion of the tube insertion hole in the core plate. The vessel is disclosed. In the heat exchanger of this patent document 1, the cutting part which is a site | part in which the burring part is not formed is provided in a part of inner peripheral part of the tube insertion hole in a core plate. By providing such a cutting portion, it is possible to prevent the burring portion from being broken when forming the burring portion. Thereby, the formability of the core plate can be improved.

JP, 2008-116101, A

  However, in the heat exchanger of Patent Document 1, the cutting portion is provided at a portion corresponding to the curved portion in the inner peripheral edge portion of the tube insertion hole in the core plate. For this reason, when the stress is generated in the tube rooted portion, a portion where the burring portion is not formed is present in the curved portion where the stress is concentrated. As a result, the effect of alleviating stress concentration by the burring portion is reduced.

  An object of the present invention is to provide a heat exchanger capable of reliably relieving stress concentration on a tube rooted portion while improving the formability of a core plate, and a method of manufacturing the same.

  In order to achieve the above object, in the invention according to claim 1, a tube (2) in which a plurality of layers are arranged and a core plate (51) which is provided at both ends in the longitudinal direction of the tube and to which the tubes are joined And a header tank (5), and a cross section orthogonal to the longitudinal direction of the tube connects a pair of linear portions (21) parallel to each other and ends of the pair of linear portions, and the longitudinal direction And a curved portion (22) curved so as to project outward in the longitudinal direction, and the longitudinal end of the tube is in the tube insertion hole (511a) of the tube joint surface (511) in the core plate It is joined in the inserted state, and the cylindrical burring part (53) which protrudes in one side is formed in the inner peripheral part of a tube insertion hole, and tube insertion is carried out. In each of the portions corresponding to the pair of linear portions in the inner peripheral edge portion, at least one cutting portion (54), which is a portion where the burring portion is cut and the burring portion is not formed, It is provided.

  According to this, since the cutting portion (54) obtained by cutting the burring portion (53) is provided at the inner peripheral edge portion of the tube insertion hole (511a), the burring portion (53) is formed when the burring portion (53) is formed. Can be prevented from breaking. Therefore, the formability of the core plate (51) can be improved.

  And since the cutting part (54) is arrange | positioned in the site | part corresponding to a pair of linear part (21) among the inner periphery parts of a tube insertion hole (511a), when a stress generate | occur | produces in a tube root attachment part A burring portion (53) is provided without break at a portion corresponding to the curved portion (22) where the stress is concentrated. For this reason, when stress is generated in the tube rooted portion, the stress can be dispersed in the burring portion (53) in the curved portion (22). Therefore, the stress applied to the curved portion (22) can be relieved, and concentration of stress on the curved portion (22) can be suppressed. This makes it possible to reliably relieve stress concentration on the tube rooted portion.

  In the invention according to claim 5, the header tank (5) is provided with the tubes (2) arranged in a plurality of stacked layers and the core plate (51) to which the tubes are joined while being provided at both ends in the longitudinal direction of the tubes. And the tube has a cross section perpendicular to the longitudinal direction connecting a pair of straight portions (21) parallel to each other and the ends of the pair of straight portions toward the outside in the longitudinal direction And a curved portion (22) which is curved so as to project, and the longitudinal end of the tube is inserted into the tube insertion hole (511a) of the tube bonding surface (511) of the core plate In the method of manufacturing a heat exchanger joined, the tube joint surface is in contact with at least one end of a first groove (71) extending in the extending direction of the linear portion and the first groove. And a groove forming step of forming a second groove (72) extending to intersect the first groove, and burring from the bottom side to the opening side of the first groove and the second groove with respect to the core plate Forming a tube insertion hole in the core plate by processing and simultaneously forming a cylindrical burring portion (53) protruding toward the opening on the inner peripheral edge of the tube insertion hole; In the process, the burring portion is cut at a portion corresponding to the second groove portion in the inner peripheral edge portion of the tube insertion hole to form a cutting portion (54) which is a portion where the burring portion is not formed, At least one cutting portion is provided at each of the portions of the inner peripheral edge portion of the tube insertion hole corresponding to the pair of linear portions.

  According to this, since the cut portion (54) obtained by cutting the burring portion (53) is provided at the inner peripheral edge portion of the tube insertion hole (511a), the burring portion (53) may be broken in the burring process. It can prevent. Therefore, the formability of the core plate (51) can be improved.

  And since the cutting part (54) is arrange | positioned in the site | part corresponding to a pair of linear part (21) among the inner periphery parts of a tube insertion hole (511a), when a stress generate | occur | produces in a tube root attachment part A burring portion (53) is provided without break at a portion corresponding to the curved portion (22) where the stress is concentrated. For this reason, when stress is generated in the tube rooted portion, the stress can be dispersed in the burring portion (53) in the curved portion (22). Therefore, the stress applied to the curved portion (22) can be relieved, and concentration of stress on the curved portion (22) can be suppressed. This makes it possible to reliably relieve stress concentration on the tube rooted portion.

  In the invention according to claim 6, the header tank (5) is provided with the tubes (2) arranged in multiple layers and the core plates (51) to which the tubes are joined while being provided at both ends of the tubes in the longitudinal direction. And the tube has a cross section perpendicular to the longitudinal direction connecting a pair of straight portions (21) parallel to each other and the ends of the pair of straight portions toward the outside in the longitudinal direction And a curved portion (22) which is curved so as to project, and the longitudinal end of the tube is inserted into the tube insertion hole (511a) of the tube bonding surface (511) of the core plate In the method of manufacturing a heat exchanger to be joined, the tube joint surface is connected to a groove (71) extending in the extending direction of the linear portion and at least one end of the groove A tube forming step of forming a through hole (73), which extends so as to intersect the groove together, and burring the core plate from the bottom side of the groove toward the opening side, thereby inserting the tube into the core plate And a burring step of forming a cylindrical burring portion (53) projecting to the opening side at the inner peripheral edge portion of the tube insertion hole at the same time as forming the hole. In the burring step, the inner peripheral edge portion of the tube insertion hole Among the portions corresponding to the through holes, the burring portion is cut to form a cut portion (54) where the burring portion is not formed, and the cut portion corresponds to the inner peripheral edge portion of the tube insertion hole. At least one is provided at each of the portions corresponding to the pair of linear portions.

  According to this, since the cut portion (54) obtained by cutting the burring portion (53) is provided at the inner peripheral edge portion of the tube insertion hole (511a), the burring portion (53) may be broken in the burring process. It can prevent. Therefore, the formability of the core plate (51) can be improved.

  And since the cutting part (54) is arrange | positioned in the site | part corresponding to a pair of linear part (21) among the inner periphery parts of a tube insertion hole (511a), when a stress generate | occur | produces in a tube root attachment part A burring portion (53) is provided without break at a portion corresponding to the curved portion (22) where the stress is concentrated. For this reason, when stress is generated in the tube rooted portion, the stress can be dispersed in the burring portion (53) in the curved portion (22). Therefore, the stress applied to the curved portion (22) can be relieved, and concentration of stress on the curved portion (22) can be suppressed. This makes it possible to reliably relieve stress concentration on the tube rooted portion.

  In addition, the code | symbol in the parenthesis of each means described by this column and the claim shows correspondence with the specific means as described in embodiment mentioned later.

It is a front view showing a radiator concerning a 1st embodiment. It is II-II sectional drawing of FIG. It is the III-III sectional view of FIG. It is the IV section enlarged view of FIG. It is explanatory drawing for demonstrating the state of the core plate of the groove part formation process in 1st Embodiment. It is the VI-VI sectional view of FIG. It is explanatory drawing for demonstrating the state of the core plate of the burring process in 1st Embodiment. It is VIII-VIII sectional drawing of FIG. It is a partially expanded view which shows the tube insertion hole periphery of the core plate which concerns on a comparative example. It is XX sectional drawing of FIG. It is XI-XI sectional drawing of FIG. It is a partially expanded view which shows the tube insertion hole periphery of the core plate in 2nd Embodiment. It is a partially expanded view which shows the tube insertion hole periphery of the core plate in 3rd Embodiment. It is sectional drawing which shows the core plate in 4th Embodiment. It is explanatory drawing for demonstrating the state of the core plate of the groove part formation process in 5th Embodiment. It is explanatory drawing for demonstrating the state of the core plate of the groove part formation process in 6th Embodiment. It is a partially expanded view which shows the tube insertion hole periphery of the core plate in other embodiment (1). It is a partially expanded view which shows the tube insertion hole periphery of the core plate in other embodiment (1).

  Hereinafter, an embodiment of the present invention will be described based on the drawings. In the following embodiments, parts identical or equivalent to each other are denoted by the same reference numerals in the drawings.

First Embodiment
A first embodiment of the present invention will be described based on FIGS. In the present embodiment, an example in which the heat exchanger according to the present invention is applied to a radiator 1 for cooling a water-cooled engine (that is, an internal combustion engine) (not shown) mounted on a vehicle will be described.

  As shown in FIG. 1, the radiator 1 of the present embodiment has a core portion 4 which is a heat exchange portion that exchanges heat of engine cooling water with the outside air. The core portion 4 is a laminate in which a plurality of tubes 2 and fins 3 are vertically stacked.

  The tube 2 is a tubular member in which a flow passage through which engine cooling water flows is formed. The tube 2 extends in the longitudinal direction along the horizontal direction. The tube 2 is formed in a flat shape so that the major axis direction of the cross section orthogonal to the longitudinal direction extends along the flow direction of the air passing through the core portion 4.

  Hereinafter, the longitudinal direction of the tube 2 is referred to as a tube longitudinal direction, and the stacking direction of the tubes 2 is referred to as a tube stacking direction. Further, in the present specification, the cross-sectional major axis direction of the tube 2 is the tube width direction. In the present embodiment, the tube width direction coincides with the direction orthogonal to both the tube longitudinal direction and the tube stacking direction.

  The fins 3 are heat transfer members that promote heat exchange between the outside air and the cooling water by increasing the heat transfer area with the outside air. The fins 3 of the present embodiment are formed in a corrugated shape (i.e., wave shape) and are joined to flat portions on both sides of the tube 2.

  The tube 2 and the fin 3 are made of a metal (e.g., an aluminum alloy) excellent in thermal conductivity, corrosion resistance, and the like. The tube 2, the fins 3, the core plate 51 to be described later, and the side plate 6 to be described later are integrally brazed by a brazing material coated at a predetermined position of each member.

  A pair of header tanks 5 extending in the tube stacking direction and having a space formed therein are disposed at both ends of each tube 2 in the tube longitudinal direction. The header tank 5 has a core plate 51 to which the tube 2 is inserted and joined, and a tank main body 52 that constitutes a tank space together with the core plate 51. The header tank 5 is brazed and joined in a state in which the tube longitudinal end of each tube 2 is inserted into a tube insertion hole 511 a described later of the core plate 51. The internal passage of each tube 2 communicates with the space formed inside the header tank 5.

  Side plates 6 for reinforcing the core portion 4 are provided at both ends of the core portion 4 in the tube stacking direction. The side plate 6 extends in parallel with the longitudinal direction of the tube, and its both ends are connected to the core plate 51. The side plate 6 of the present embodiment is made of a metal such as an aluminum alloy.

  Here, among the pair of header tanks 5, one header tank 5 is referred to as a first header tank 5a, and the other header tank 5 is referred to as a second header tank 5b.

  At the upper end portion of the first header tank 5a, an inflow port 61 for allowing cooling water to flow into the in-tank space of the first header tank 5a is provided. At the lower end portion of the second header tank 5b, an outlet 62 for allowing the cooling water to flow out of the space in the second header tank 5b is provided.

  As shown in FIGS. 2 and 3, the header tank 5 has a core plate 51 and a tank body 52. The core plate 51 is a plate-like member to which the tube 2 and the side plate 6 are inserted and joined. The tank main body 52 constitutes a tank internal space which is a space in the header tank 5 together with the core plate 51.

  The core plate 51 of the present embodiment is formed of a metal (for example, an aluminum alloy) excellent in thermal conductivity, corrosion resistance, and the like. The tank body 52 of this embodiment is formed of a resin such as glass reinforced polyamide reinforced with glass fiber.

  Next, detailed configurations of the tube 2 and the core plate 51 will be described based on FIG. 2, FIG. 3 and FIG. In FIGS. 2 and 4, the vertical direction in the drawing is the tube longitudinal direction, and in FIG. 4, the vertical direction in the drawing is the tube stacking direction. In addition, in FIG. 2 and FIG. 4, the burring part 53 mentioned later is shown by dot hatching for clarification of illustration, and illustration of the tube 2 is abbreviate | omitted in FIG.

  As shown in FIG. 2, the tube 2 is formed in a flat shape in cross section. Specifically, the cross section perpendicular to the longitudinal direction of the tube 2 has a pair of linear portions 21 parallel to each other, and a pair of curved portions 22 connecting the ends of the pair of linear portions 21 There is.

  The straight portion 21 extends parallel to the air flow direction. That is, the extending direction of the linear portion 21 coincides with the tube width direction. The curved portion 22 is curved so as to protrude outward in the longitudinal direction of the tube in a cross section perpendicular to the longitudinal direction of the tube. In the present embodiment, the curved portion 22 is formed in an arc shape projecting outward in the tube longitudinal direction.

  The core plate 51 is formed with a tube joint surface 511 to which the tube 2 is inserted and joined. The tube joint surface 511 is formed flat. That is, the tube joint surface 511 is configured by a flat surface. The tube joint surface 511 is formed to intersect the tube longitudinal direction and to extend in the tube width direction. The tube joint surface 511 in the present embodiment is formed orthogonal to the longitudinal direction of the tube and in parallel to the width direction of the tube.

  In the tube joint surface 511, a plurality of tube insertion holes 511a are formed. The plurality of tube insertion holes 511 a are formed to be arranged at predetermined intervals in the tube stacking direction. The longitudinal end of the tube 2 is brazed and joined to the tube insertion hole 511a.

  A groove-shaped accommodation receiving portion 512 is formed around the tube bonding surface 511 of the core plate 51. The accommodation receiving portion 512 accommodates the leading end portion of the tank body 52 and a packing (not shown). The packing is a seal member that seals between the core plate 51 and the tank main body 52. The packing is made of, for example, silicone rubber or EPDM (i.e., ethylene propylene diene rubber).

  As shown in FIG. 3, the accommodation receiving portion 512 has three wall surfaces including a bottom wall portion 512 b extending in the tube width direction, and an inner side wall portion 512 a and an outer wall portion 512 c extending in the tube longitudinal direction. These wall surfaces are formed in the order of the inner wall portion 512a, the bottom wall portion 512b, and the outer wall portion 512c from the tube joint surface 511.

  The inner side wall portion 512a and the outer side wall portion 512c are each formed by being bent in an L shape from the bottom wall portion 512b. The inner side wall 512a is located closer to the tube 2 than the bottom wall 512b in the tube width direction, and the outer wall 512c is located farther from the tube 2 than the bottom wall 512b.

  The inner side wall portion 512a is disposed outside the tube 2 in the tube width direction. That is, the entire accommodation receiving portion 512 of the core plate 51 is disposed outside the tube 2 in the tube width direction.

  The core plate 51 is provided with a plurality of projecting pieces 515. The projecting pieces 515 are formed to project from the outer side wall 512 c of the core plate 51 to the tank main body 52 side.

  Then, in a state in which the packing is sandwiched between the core plate 51 and the tank main body 52, the projecting piece 515 of the core plate 51 is plastically deformed so as to press the tank main body 52, and the tank main body 52 is core plate 51 It is fixed by caulking. The tank body 52 is assembled to the core plate 51 by caulking and fixing the projecting piece 515 to the flange 522 of the tank body 52.

  The leading end of the tank body 52 is disposed on the bottom wall 512 b of the core plate 51 via a packing. That is, the bottom wall portion 512b constitutes a sealing surface on which the packing is disposed.

  As shown in FIGS. 2 and 3, at the inner peripheral edge portion of the tube insertion hole 511 a in the core plate 51, a cylindrical burring portion 53 which protrudes to one side is formed. The burring part 53 is formed by performing hole flange processing (that is, burring processing) on the edge of the tube insertion hole 511a which is a through hole. The details of the method of manufacturing the burring portion 53 will be described later.

  The burring portion 53 constitutes the outer peripheral edge portion of the tube insertion hole 511a. The tube 2 is joined to the inner circumferential surface of the burring portion 53.

  The burring portion 53 extends in the extending direction (that is, the longitudinal direction) of the tube 2. This is for the tube 2 to easily absorb the stress of the tube 2 when it extends in the longitudinal direction of the tube.

  In the present embodiment, the burring portion 53 protrudes from the tube joint surface 511 toward the outside in the longitudinal direction of the tube 2 (that is, the inward side of the header tank 5). That is, the burring portion 53 is disposed on the opposite side to the core portion 4 with respect to the tube bonding surface 511.

  At the inner peripheral edge portion of the tube insertion hole 511a, a cutting portion 54 which is a portion where the burring portion 53 is cut and the burring portion 53 is not formed is provided. In other words, in each of the tube insertion holes 511a, a portion where the burring portion 53 is not formed is provided at the inner peripheral edge portion of the tube insertion hole 511a.

  Next, detailed configurations of the burring portion 53 and the cutting portion 54 in the present embodiment will be described based on FIGS. 2, 3 and 4. In addition, in FIG. 4, the burring part 53 is shown by dot hatching for clarification of illustration.

  Here, in the linear portion 21 of the tube 2, a portion connected to the bending portion 22 is referred to as a connection portion 21 a. Further, a portion corresponding to the linear portion 21 of the tube 2 in the tube insertion hole 511a (more specifically, the inner peripheral portion of the tube insertion hole 511a) is referred to as a linear edge 55 and a portion corresponding to the curved portion 22. Is called an arc-shaped edge 56, and a portion corresponding to the connection portion 21a is called a connection edge 55a.

  As shown in FIG. 2 and FIG. 4, in the present embodiment, the cutting portions 54 are provided at four places in the inner peripheral edge portion of the tube insertion hole 511 a. Specifically, two cutting portions 54 are provided at each of the portions corresponding to the pair of linear portions 21 in each tube insertion hole 511a. That is, in each of the tube insertion holes 511 a, two cutting portions 54 are provided in each of the pair of linear edge portions 55.

  In more detail, the cutting part 54 is provided in the site | part corresponding to the connection part 21a in the tube insertion hole 511a. That is, in each tube insertion hole 511a, one cutting portion 54 is provided at each connection edge 55a.

  As shown in FIG. 3, in the present embodiment, the length of the cutting portion 54 in the tube width direction is constant in the tube longitudinal direction. That is, the whole area of the end face on the outer side of the header tank 5 in the longitudinal direction of the tube in the cutting portion 54 is disposed on a virtual plane perpendicular to the longitudinal direction of the tube. The outer side of the header tank 5 in the longitudinal direction of the tube is the side opposite to the core portion 4 in the longitudinal direction of the tube, and indicates the left side in the drawing of FIG.

Here, a distance between an end of the burring portion 53 on the side far from the tube bonding surface 511 and the tube bonding surface 511 is taken as a burring dimension H. Further, the burring dimension H of the burring portion 53 formed at positions corresponding to the straight portion 21 of the tube insertion hole 511a (i.e. straight-like rim portion 55), and straight portion burring dimension H _1. Further, the burring dimension H of the burring portion 53 formed at positions corresponding to the curved portion 22 of the tube insertion hole 511a (i.e. arc-like rim portion 56), and the curved portion burring dimension H _2. At this time, the curved portion burring dimension H ₂ is higher than the linear portion burring dimension H _1.

Here, as shown in FIG. 4, of the both end portions in the tube width direction of the cutting portion 54, an end portion on the side closer to the center portion in the tube width direction of the tube 2 is taken as a central side end portion 54 a. The end portion of the tube width direction of the burring portion 53 (hereinafter, referred to as the width direction end portion 53a) the distance of the tube width direction from to the center-side end portion 54a, a cut portion distance D _c. At this time, the core plate 51 is configured to satisfy the relationship of 1.0 ≦ H ₂ (H ₁ + D _c ) ≦ 1.5.

  Next, the manufacturing method of the burring part 53 of this embodiment is demonstrated using FIGS. 5-8.

[Groove formation process]
As shown in FIG. 5 and FIG. 6, a groove forming step of forming the first groove 71 and the second groove 72 on the tube joint surface 511 of the core plate 51 is performed. In addition, the part shown with a dashed-dotted line in FIG. 5 is a part used as the outer periphery part of the tube insertion hole 511a after the burring process mentioned later. Therefore, at the time of the actual groove formation process, nothing is formed in the portion shown by the alternate long and short dash line in FIG.

  The first groove 71 extends in the extending direction of the linear portion 21 (i.e., the tube width direction). The second groove 72 is connected to both ends of the first groove 71. In addition, the second groove 72 extends so as to intersect the first groove 71. In the present embodiment, the second groove 72 is orthogonal to the first groove 71. That is, the second groove 72 extends in the tube stacking direction.

[Burring process]
Next, as shown in FIGS. 7 and 8, the core plate 51 in which the grooves 71 and 72 are formed is subjected to burring from the bottom surface side of the grooves 71 and 72 toward the opening side. Thus, the tube insertion hole 511a is formed in the core plate 51, and at the same time, the cylindrical burring portion 53 protruding toward the opening of the groove portions 71 and 72 is formed in the inner peripheral edge of the tube insertion hole 221.

  At this time, the cutting portion 54 is formed in a portion corresponding to the second groove portion 72 in the inner peripheral edge portion of the tube insertion hole 511a. In the present embodiment, two cutting portions 54 are provided in each of the portions corresponding to the pair of linear portions 21 in the inner peripheral edge portion of the tube insertion hole 511a. Thereby, the core plate 51 in which the burring part 53 and the cutting part 54 of this embodiment were formed can be obtained.

  As described above, in the present embodiment, the cutting portion 54 in which the burring portion 53 is cut is provided at the inner peripheral edge portion of the tube insertion hole 511 a in the core plate 51. According to this, it is possible to prevent the burring portion 53 from being broken when the burring portion 53 is formed. Therefore, the formability of the core plate 51 can be improved.

  Furthermore, in the present embodiment, the cutting portion 54 is disposed at each of the portions corresponding to the pair of linear portions 21 in the inner peripheral edge portion of the tube insertion hole 511a. According to this, the burring portion 53 is provided without a break at a portion corresponding to the curved portion 22 where the stress is concentrated when the stress is generated in the tube rooted portion. Therefore, when stress is generated in the tube rooted portion, the stress can be dispersed in the burring portion 53 in the curved portion 22. Therefore, the stress applied to the curved portion 22 can be alleviated, and concentration of the stress on the curved portion 22 can be suppressed. This makes it possible to reliably relieve stress concentration on the tube rooted portion.

  Here, as a comparative example, as shown in FIG. 9 and FIG. 10, there is a configuration in which the cutting portion 54 is provided at a portion corresponding to the curved portion 22 in the tube insertion hole 511a. In this configuration, when high temperature cooling water flows through the tube 2, the tube 2 thermally expands in the direction of the arrow in FIG. Then, due to the thermal expansion difference between the tube 2 and the core plate 51, thermal distortion occurs in the joint between the tube 2 and the core plate 51.

  At this time, in the comparative example, the burring portion 53 is not provided at a portion corresponding to the curved portion 22 in the tube insertion hole 511a, and the bonding area between the curved portion 22 and the core plate 51 is reduced. For this reason, thermal distortion may concentrate on the joint between the curved portion 22 and the core plate 51, and a crack may occur in the joint due to the thermal distortion.

  On the other hand, in the present embodiment, as shown in FIG. 11, when the high temperature cooling water flows through the tube 2, the tube 2 thermally expands in the arrow direction of FIG. At this time, in the present embodiment, since the burring portion 53 is provided at a portion of the tube insertion hole 511a corresponding to the curved portion 22, the bonding area between the curved portion 22 and the core plate 51 is larger than that of the comparative example. For this reason, since the thermal distortion which generate | occur | produced in the junction part of the curved part 22 and the core plate 51 is disperse | distributed to the burring part 53, concentration of the thermal distortion to the said junction part is relieved.

Further, in the present embodiment, the bending portion burring dimension H _2, are higher than the linear portion burring dimension H _1. According to this, when the stress is generated in the tube rooted portion, the height of the burring portion 53 at the portion corresponding to the curved portion 22 where the stress is concentrated can be increased. Therefore, when the stress is generated in the tube rooted portion, the burring can be performed. The stress can be distributed to the portion 53 with certainty. Therefore, concentration of stress on the curved portion 22 can be suppressed more reliably.

Further, in the present embodiment, the core plate 51 is configured to satisfy the relationship of 1.0 ≦ H ₂ (H ₁ + D _c ) ≦ 1.5. According to this, the stress concentration effect on the tube rooted portion can be improved by setting 1.0 ≦ H ₂ (H ₁ + D _c ). Further, by setting H ₂ (H ₁ + D _c ) ≦ 1.5, the formability of the core plate 51 can be secured.

Second Embodiment
Next, a second embodiment of the present invention will be described based on FIG. The present embodiment is different from the first embodiment in the shape of the cutting portion 54.

  As shown in FIG. 12, in the present embodiment, the cutting portion 54 extends so as to intersect both the tube width direction and the tube stacking direction. More specifically, the cutting portion 54 is formed so as to approach the width direction end portion 53a as it approaches the tube insertion hole 511a.

  The other configuration of the radiator 1 is the same as that of the first embodiment. Therefore, also in the radiator 1 of this embodiment, the same effect as that of the first embodiment can be obtained.

Third Embodiment
Next, a third embodiment of the present invention will be described based on FIG. The present embodiment is different from the first embodiment in the shape of the cutting portion 54.

  As shown in FIG. 13, in the present embodiment, the cutting portion 54 is formed to be farther from the width direction end portion 53 a as it approaches the tube insertion hole 511 a. The other configuration of the radiator 1 is the same as that of the first embodiment. Therefore, also in the radiator 1 of this embodiment, the same effect as that of the first embodiment can be obtained.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described based on FIG. The present embodiment is different from the first embodiment in the shape of the cutting portion 54.

  As shown in FIG. 14, in the present embodiment, the cutting portion 54 is formed such that the length in the tube width direction is as short as the core portion 4 side in the tube longitudinal direction (that is, the right side in FIG. 14). There is. That is, the end surface on the outer side of the header tank 5 in the longitudinal direction of the tube in the cutting portion 54 is formed to be closer to the core portion 54 toward the outer side in the tube width direction.

  The other configuration of the radiator 1 is the same as that of the first embodiment. Therefore, also in the radiator 1 of this embodiment, the same effect as that of the first embodiment can be obtained.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described based on FIG. The present embodiment is different from the first embodiment in the groove forming step in the method of manufacturing the core plate 51. A portion shown by a dashed dotted line in FIG. 15 is a portion to be an outer peripheral edge portion of the tube insertion hole 511a after the burring step.

  In the groove forming step in the present embodiment, as shown in FIG. 15, the first groove 71 and a flat through hole 73 are formed in the tube bonding surface 511 of the core plate 51. The through holes 73 are connected to both end portions of the first groove portion 71. The longitudinal direction of the through hole 73 intersects the first groove 71. In the present embodiment, the longitudinal direction of the through hole 73 is orthogonal to the first groove portion 71. That is, the longitudinal direction of the through hole 73 is parallel to the tube stacking direction.

  The manufacturing method and configuration of the other radiators 1 are the same as those of the first embodiment. Therefore, also in the radiator 1 of this embodiment, the same effect as that of the first embodiment can be obtained.

Sixth Embodiment
Next, a sixth embodiment of the present invention will be described based on FIG. The present embodiment is different from the first embodiment in the groove forming step in the method of manufacturing the core plate 51. In addition, the part shown with a dashed-dotted line in FIG. 16 is a part used as the outer periphery part of the tube insertion hole 511a after a burring process.

  In the groove forming step in the present embodiment, as shown in FIG. 16, the second groove 72 is curved so as to protrude inward in the tube width direction. The first groove 71 is connected to the innermost portion of the second groove 72 in the tube width direction.

  The manufacturing method and configuration of the other radiators 1 are the same as those of the first embodiment. Therefore, also in the radiator 1 of this embodiment, the same effect as that of the first embodiment can be obtained.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be variously modified as follows, for example, within the scope of the present invention. In addition, the means disclosed in each of the above embodiments may be combined as appropriate in the feasible range.

  (1) In the above-described embodiment, an example in which the cutting portions 54 are respectively provided in portions corresponding to both end portions of the pair of linear portions 21 in the inner peripheral edge portion of the tube insertion hole 511a has been described. That is, in the above-described embodiment, an example in which one cutting portion 54 is provided in each of the inner peripheral edge portions of the tube insertion hole 511a corresponding to both end portions of the pair of linear portions 21 has been described. However, the arrangement of the cutting portion 54 is not limited to this.

  For example, as shown in FIG. 17, the cutting portion 54 may be provided at a portion corresponding to other than the both end portions of the pair of linear portions 21 in the inner peripheral edge portion of the tube insertion hole 511a.

  Further, for example, as shown in FIG. 18, one cutting portion 54 may be provided at a portion corresponding to one end portion of the pair of linear portions 21 in the inner peripheral edge portion of the tube insertion hole 511a. In this case, the cutting portion 54 may be formed by providing the second groove 72 or the through hole 73 at one end of the first groove 71 in the groove forming step.

  (2) In the above embodiment, the heat exchanger according to the present invention has been described as being applied to a radiator. However, the present invention is not limited to this and may be applied to other heat exchangers such as an evaporator and a condenser. .

Reference Signs List 2 tube 5 header tank 21 straight portion 22 curved portion 51 core plate 53 barring portion 54 cut portion 511 tube joint surface 511 a tube insertion hole

Claims (6)

Multiple stacked tubes (2),
A header tank (5) having core plates (51) provided at both longitudinal ends of the tube and to which the tube is joined;
A cross section orthogonal to the longitudinal direction of the tube connects the pair of straight portions (21) parallel to each other and the end portions of the pair of linear portions and projects outward in the longitudinal direction And a curved portion (22),
The longitudinal end of the tube is joined in a state of being inserted into the tube insertion hole (511a) of the tube joint surface (511) of the core plate,
At the inner peripheral edge of the tube insertion hole, a cylindrical burring portion (53) projecting to one side is formed,
A cutting portion (54 in which the burring portion is cut and the burring portion is not formed in each of the portions corresponding to the pair of linear portions in the inner peripheral edge portion of the tube insertion hole A heat exchanger provided with at least one). When the site | part connected with the said curved part in the said linear part is made into a connection part (21a),
The heat exchanger according to claim 1, wherein the cutting portion is provided at a portion corresponding to the connection portion in the tube insertion hole. A distance between an end of the burring portion far from the tube bonding surface and the tube bonding surface is a burring dimension (H).
The burring dimension of the burring portion formed at a portion corresponding to the linear portion in the tube insertion hole is a linear portion burring dimension (H ₁ ),
When the burring dimension of the burring portion formed at a portion corresponding to the curved portion in the tube insertion hole is a curved portion burring dimension (H ₂ ),
The heat exchanger according to claim 1, wherein the curved portion burring dimension is higher than the straight portion burring dimension. The extending direction of the linear portion is a tube width direction,
Among the both end portions in the tube width direction at the cutting portion, the end portion on the side closer to the center portion in the tube width direction of the tube is a center side end portion (54a),
When the distance in the tube width direction from the end (53a) in the tube width direction at the burring portion to the center side end is a cutting portion distance D _c ,
The heat exchanger according to claim 3, wherein the core plate is configured to satisfy a relationship of 1.0 ≦ H ₂ (H ₁ + D _c ) ≦ 1.5. Multiple stacked tubes (2),
A header tank (5) having core plates (51) provided at both longitudinal ends of the tube and to which the tube is joined;
The tube has a cross section orthogonal to the longitudinal direction connecting a pair of linear portions (21) parallel to each other and the end portions of the pair of linear portions, and protrudes outward in the longitudinal direction And a curved portion (22) curved as
A method of manufacturing a heat exchanger, wherein longitudinal ends of the tubes are joined in a state of being inserted into a tube insertion hole (511a) of a tube joint surface (511) of the core plate,
A second groove (71) extending in the extending direction of the linear portion, and a second groove (27) connected to at least one end of the first groove and extending to intersect the first groove. A groove forming step of forming a groove (72);
The core plate is burred from the bottom side of the first groove and the second groove toward the opening side to form the tube insertion hole in the core plate and at the same time And b) forming a cylindrical burring portion (53) projecting to the opening side at the inner peripheral edge portion, and
In the burring step, a cutting portion (54) in which the burring portion is cut at a portion corresponding to the second groove portion in the inner peripheral edge portion of the tube insertion hole, and the burring portion is not formed. A method of manufacturing a heat exchanger, wherein the cutting portion is provided at least one at each of portions corresponding to the pair of linear portions in the inner peripheral edge portion of the tube insertion hole. Multiple stacked tubes (2),
A header tank (5) having core plates (51) provided at both longitudinal ends of the tube and to which the tube is joined;
The tube has a cross section orthogonal to the longitudinal direction connecting a pair of linear portions (21) parallel to each other and the end portions of the pair of linear portions, and protrudes outward in the longitudinal direction And a curved portion (22) curved as
A method of manufacturing a heat exchanger, wherein longitudinal ends of the tubes are joined in a state of being inserted into a tube insertion hole (511a) of a tube joint surface (511) of the core plate,
A groove (71) extending in the extension direction of the linear portion and a through hole (73) connected to at least one end of the groove and extending to intersect the groove are formed in the tube bonding surface Groove forming process,
The core plate is subjected to burring processing from the bottom surface side of the groove toward the opening side, thereby forming the tube insertion hole in the core plate and at the same time the opening side in the inner peripheral edge of the tube insertion hole Forming a cylindrical burring portion (53) protruding into the
In the burring step, a cutting portion (54) is a portion at which the burring portion is cut and the burring portion is not formed at a portion corresponding to the through hole in the inner peripheral edge portion of the tube insertion hole A method of manufacturing a heat exchanger, wherein the cutting portion is formed at least one in each of the portions corresponding to the pair of linear portions in the inner peripheral edge portion of the tube insertion hole.

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