Heat exchanger

Abstract

To provide a heat exchanger which can suppress the generation of cracks at a brazed part of a core of a thin plate.SOLUTION: In a heat exchanger (EGR cooler 1) of the present invention, a bottom wall part 310 of a bracket 3 having a bent R-part 313 which is formed of a sheet metal is brazed to a shell outside face 200 of a shell 20 of a core 2 of a thin plate via a flat plate-shaped spacer 7 which is thicker than the core 2 (shell 20). Therefore, there is no risk that a so-called wedge-shaped fragile part is formed at the shell outside face 200 of the core 2 (shell 20) of the thin plate, and a brazed peripheral edge part of a spacer lower face 72 of the spacer 7. By this constitution, the generation of cracks at a brazed part which is brazed to the spacer 7 of the core 2 (shell 20) of the thin plate caused by the formation of the fragile part can be suppressed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a heat exchanger. [Background technology]

[0002] A known conventional heat exchanger is, for example, that described in Patent Document 1 below.

[0003] To explain briefly, in this heat exchanger, a reinforcing member is provided at an end in the lamination direction of a core made of thin plates, and a bracket is brazed to the reinforcing member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-007672 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional heat exchangers have room for improvement in that the thick plate reinforcing members are provided at the ends in the stacking direction, which increases the weight and manufacturing costs of the heat exchanger.

[0006] In particular, when a bracket having a so-called bent radius portion is brazed to a core whose end in the lamination direction is made of a thin plate, the area between the bent radius portion and the thin plate forms a so-called wedge shape, which makes it easy for cracks to occur in the brazed portion between the bracket and the thin plate, leaving room for improvement.

[0007] Therefore, the present invention has been devised in consideration of the technical problems of the conventional heat exchangers, and aims to provide a heat exchanger that can suppress the occurrence of cracks in the brazed portion of the thin plate core. [Means for solving the problem]

[0008] In one aspect of the present invention, an outer bottom surface of a bracket having a bend radius formed from sheet metal is brazed to an exterior of a core made of a thin plate via a flat spacer. Effect of the Invention

[0009] According to the present invention, since the bracket having the bent radius made of sheet metal is brazed to the thin plate core via the plate-shaped spacer, there is no risk of a wedge-shaped weak portion being formed at the brazed end between the thin plate and the spacer, and therefore it is possible to suppress the occurrence of cracks in the brazed portion of the thin plate core caused by the formation of the wedge-shaped weak portion. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of the heat exchanger according to the present invention. [Diagram 2] 2 is a view taken along the arrow A in FIG. 1. [Diagram 3] FIG. 3 is an enlarged view of a main part of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat exchanger according to an embodiment of the present invention will be described below in detail with reference to the drawings. In the following embodiment, an example in which the heat exchanger according to the present invention is applied to an EGR cooler of an automobile engine will be described.

[0012] Fig. 1 shows a plan view of an EGR cooler 1 according to this embodiment. Fig. 2 shows a view seen from the direction of an arrow A in Fig. 1. Fig. 3 shows an enlarged view of a main part of Fig. 2, which shows an enlarged view of a part B in Fig. 2.

[0013] The EGR cooler 1 shown in FIG. 1 and FIG. 2 includes a cylindrical core 2 for exchanging heat between fluids, and a bracket 3 for mounting the core 2 to an engine (not shown). A gas inlet pipe 41 for introducing exhaust gas discharged from an engine (not shown) is connected to one longitudinal end of the core 2. The gas inlet pipe 41 is connected to the exhaust side of the engine (not shown) via a gas inlet pipe flange 410 provided at the tip of the gas inlet pipe 41. On the other hand, a gas outlet 42 for discharging exhaust gas cooled inside the core 2 is provided at the other longitudinal end of the core 2. A gas outlet flange 420 is provided at the opening of the gas outlet 42, and the gas outlet 42 is connected to the intake side of the engine (not shown) via the gas outlet flange 420. Furthermore, a refrigerant inlet pipe 51 is connected to one longitudinal end of the core 2 on the side thereof, and is used for introducing cooling water, which corresponds to the refrigerant in this embodiment, and a refrigerant outlet pipe 52 is connected to the other longitudinal end of the core 2, and is used for discharging the cooling water.

[0014] As shown in Figs. 1 and 2, the core 2 is a core body (not shown) that constitutes a fluid passage through which the exhaust gas flows as a fluid and a cooling passage through which the cooling water flows as a refrigerant, and is housed inside a shell 20 made of a stainless steel thin plate. The shell 20 is formed in a square tube shape with a roughly rectangular cross section, and one end opening in the longitudinal direction is closed by a gas introduction member 61, and the other end opening in the longitudinal direction is closed by a gas discharge member 62. The gas introduction member 61 has a gas introduction pipe 41 connected to a side of the gas introduction member 61, and introduces the exhaust gas introduced from a direction perpendicular to the longitudinal direction of the shell 20 through the gas introduction pipe 41 into the inside of the core 2. On the other hand, the gas discharge member 62 leads the exhaust gas cooled inside the core 2 to the intake side of the engine (not shown).

[0015] As described above, in the EGR cooler 1, high-temperature exhaust gas is introduced through the gas introduction pipe 41, passes through the gas introduction member 61 and flows into the inside (fluid passage) of the core 2, where heat exchange with the cooling water takes place inside the core 2, and the cooled exhaust gas is discharged from the core 2 through the gas discharge member 62. In addition, low-temperature cooling water passes through the gas introduction member 61 from the refrigerant introduction pipe 51 and flows into the inside (cooling passage) of the core 2, where heat exchange with the exhaust gas takes place inside the core 2, and the heated cooling water is discharged from the core 2 through the refrigerant discharge pipe 52.

[0016] 1 and 2, the bracket 3 has a core connection part 31 connected to the core 2 by brazing, and an engine coupling part 32 provided integrally with the core connection part 31 and coupled to an engine (not shown) by a predetermined fastening means, and these are integrally formed from stainless steel metal. Here, the core connection part 31 is formed by bending a metal plate so that its cross section is substantially U-shaped, and the engine coupling part 32 is formed in a flat plate shape from a metal plate and joined to one end of the core connection part 31 in the longitudinal direction by, for example, welding, so that the core connection part 31 and the engine coupling part 32 are integrally formed.

[0017] As shown in Figs. 1 to 3, the core connection part 31 is brazed to a spacer upper surface 71, which is one side surface in the thickness direction of the spacer 7 formed in a substantially rectangular flat plate shape, via a brazing material BM (see Fig. 3), and is integrally formed with a flat bottom wall part 310 joined to the core 2 via the spacer 7, and a pair of side wall parts, a first side wall part 311 and a second side wall part 312, which rise substantially vertically in a direction away from the core 2 via a bent radius part 313 bent in an arc shape from both sides of the bottom wall part 310. The core connection part 31 extends in a direction perpendicular to the longitudinal direction of the core 2, and one end side in the longitudinal direction overlaps with the core 2 and is connected to the core 2, while the other end side overhangs to the outside of the core 2 (see Fig. 1). Here, the bottom wall part 310 of the core connection part 31 is joined to the spacer 7 over the entire surface of a bracket outer bottom surface 310a facing the spacer 7.

[0018] 1 and 2, the engine connecting part 32 is formed in a plate shape that closes one longitudinal end of the core connecting part 31, and a peripheral part that faces the core connecting part 31 is welded to the core connecting part 31. The engine connecting part 32 has a circular through hole 320 at the center, and is connected to an engine (not shown) via a predetermined fastening means such as a bolt that passes through the through hole 320.

[0019] As shown in Fig. 1, the spacer 7 is made of stainless steel metal, which is the same metal as the bracket 3, and is formed in a plate shape having a substantially rectangular shape in a plan view, and is joined by brazing to the shell outer surface 200 of the shell 20 of the core 2 with a joint area S2 larger than the joint area S1 with the bottom wall portion 310 of the bracket 3. That is, as shown in Figs. 2 and 3, the spacer 7 is formed in a flat plate shape having a substantially constant thickness that is thicker than the shell 20 of the core 2, which is formed to be relatively thin, and is the same thickness as the bottom wall portion 310 of the bracket 3, and the entire surface of the spacer lower surface 72, which is the other side surface of the spacer 7 in the thickness direction facing the core 2, is brazed to the shell outer surface 200 of the core 2 (shell 20) via the brazing material BM (see Fig. 3). In other words, the brazing area (joint area S2) between the spacer 7 and the core 2 (shell 20) is configured to be larger than the brazing area (joint area S1) between the spacer 7 and the bracket 3 (bottom wall portion 310).

[0020] In this embodiment, when brazing, the shell 20 of the core 2 and the spacer 7 formed from sheet metal are respectively coated with brazing material, and these are heated in a furnace, thereby brazing the bracket 3 and the spacer 7, and brazing the spacer 7 and the core 2. In addition to applying the brazing material to the shell 20 of the core 2 and the spacer 7 to perform brazing as in this embodiment, it is also possible to use a so-called clad material in which the metal surface is coated with the brazing material in advance. In other words, the clad material may be processed into sheet metal to form the bracket 3 and the spacer 7, and these may be heated in a furnace to braze the bracket 3, the spacer 7, and the core 2.

[0021] (Effects of this embodiment) In the case of the conventional heat exchanger, a thick plate reinforcing member is provided on the shell 20 of the core 2. This leads to an increase in the weight and manufacturing cost of the heat exchanger, and there is still room for improvement.

[0022] In particular, when the bracket 3 having the curved radius portion 313 is brazed to the core 2 formed from a thin plate, a so-called wedge shape is formed between the thin plate core 2 and the curved radius portion 313. This means that cracks are likely to occur in the brazed portion between the thin plate core 2 and the bracket 3, and there is still room for improvement.

[0023] In contrast, in the heat exchanger (EGR cooler 1) according to the present embodiment, the bottom wall portion 310 of the bracket 3 having the bent radius portion 313 formed by sheet metal is brazed to the shell outer surface 200 of the thin core 2 (shell 20) via a flat spacer 7 thicker than the core 2 (shell 20). At this time, the shell outer surface 200 of the core 2 (shell 20) and the spacer lower surface 72 are both formed flat and face each other approximately parallel. Therefore, there is no risk of a wedge-shaped weak portion being formed as in the conventional method at the brazed peripheral portion between the shell outer surface 200 of the thin core 2 (shell 20) and the spacer lower surface 72 of the spacer 7. This makes it possible to suppress the occurrence of cracks in the brazed portion between the thin core 2 (shell 20) and the spacer 7 as in the conventional method, which are caused by the formation of the wedge-shaped weak portion.

[0024] This makes it possible to support the bracket 3 only on a single surface of the core 2 (shell 20) made of a thin plate, without supporting the bracket 3 on multiple surfaces of the core 2 (shell 20). As a result, it is possible to suppress restrictions on the layout of the bracket 3, which arise when supporting the bracket 3 on multiple surfaces, and to suppress increases in weight and cost of the bracket 3.

[0025] In addition, as a means for avoiding the occurrence of cracks in the brazed portion with the thin plate, a method of forming the bracket 3 integrally with a flange of the heat exchanger (for example, the gas exhaust port flange 420 in this embodiment) has been conventionally adopted. However, when the bracket 3 is formed integrally with the flange of the heat exchanger (the gas exhaust port flange 420), there is a problem that the layout of the bracket 3 is restricted.

[0026] In contrast, in the heat exchanger (EGR cooler 1) according to the present invention, as described above, the bracket 3 is brazed to the thin core 2 (shell 20) via the flat spacer 7, so that the arrangement of the bracket 3 is not subject to restrictions, and the degree of freedom in the layout of the bracket 3 can be improved. In addition, by making the bracket 3 separate from the flange (gas exhaust port flange 420) of the heat exchanger and making the bracket 3 out of sheet metal, it is possible to contribute to suppressing an increase in the cost of the EGR cooler 1, which is a heat exchanger.

[0027] In this embodiment, the brazing area (joint area S2) between the shell outer surface 200 of the core 2 (shell 20) and the spacer lower surface 72 of the spacer 7 is larger than the brazing area (joint area S1) between the outer bottom surface of the bottom wall portion 310 of the bracket 3 and the spacer 7. Therefore, stress generated in the brazed portion of the core 2 is effectively dispersed, and the durability of the brazed portion of the core 2 can be improved.

[0028] In addition, since the brazing area (joint area S1) between the bracket 3 and the spacer 7 is set relatively small, the bracket 3 only needs to have a minimum size on the outer bottom surface of the bottom wall portion 310 to distribute the stress in the brazing portion of the core 2 made of a thin plate, and the bracket 3 can be made compact. This contributes to reducing the weight and cost increase of the EGR cooler 1, which is a heat exchanger.

[0029] In addition, in the square tubular EGR cooler 1 having a plurality of side surfaces made of thin plates on the outer periphery of the core 2 (shell 20), the bracket 3 can be supported by the plurality of side surfaces of the core 2 (shell 20), but in this embodiment, the bracket 3 is brazed to a single surface of the shell outer side surface 200 of the core 2 (shell 20) via the spacer 7. This allows the bracket 3 to be made smaller and improves the degree of freedom in layout of the bracket 3.

[0030] Furthermore, in the above-mentioned embodiment in which the bracket 3 is integrally formed with the flange of the heat exchanger (the gas exhaust port flange 420 in this embodiment), machining of the bracket 3 is required. However, if the bracket 3 is made of stainless steel, the machining cost of the bracket 3 increases, resulting in an increase in the cost of the EGR cooler 1.

[0031] In contrast, in this embodiment, the core 2, bracket 3, and spacer 7 are all made of stainless steel metal, and the bracket 3 is made of sheet metal. This makes it possible to omit machining of the bracket 3, which contributes to reducing the manufacturing cost of the EGR cooler 1, which is a heat exchanger.

[0032] The present invention is not limited to the configurations exemplified in the above-described embodiments, and can be freely modified according to, for example, the specifications of the heat exchanger to which the present invention is applied.

[0033] For example, in the present embodiment, an example has been given of the heat exchanger according to the present invention being applied to an EGR cooler of an automobile engine, but the heat exchanger according to the present invention can also be applied to other heat exchangers, such as radiators, intercoolers, oil coolers, etc., in addition to the above-mentioned EGR coolers.

[0034] In addition, the materials of the core 2, the bracket 3, and the spacer 7 are not limited to stainless metal, and any metal material can be used according to the specifications of the heat exchanger (EGR cooler 1). In particular, when using cooling water as in this embodiment, it is preferable to use a highly corrosion-resistant metal material such as aluminum or copper.

[0035] Moreover, the present invention is not limited to the configuration of this embodiment, and the brazing area (bonding area S2) between the spacer 7 and the core 2 (shell 20) and the brazing area (bonding area S1) between the spacer 7 and the bracket 3 (bottom wall portion 310) can be arbitrarily changed according to the specifications of the heat exchanger (EGR cooler 1) to which the present invention is applied. In other words, as in the above embodiment, it is not necessarily the case that the brazing area (bonding area S2) between the outer shell surface 200 of the core 2 (shell 20) and the spacer 7 and the brazing area (bonding area S1) between the bottom wall portion 310 of the bracket 3 and the spacer 7 have the relationship of "S1 < S2", and for example, it may be configured such that "S1 = S2" or "S1 > S2".

Explanation of Reference Numerals

[0036] 1... EGR cooler (heat exchanger) 2... Core 20... Shell 200... Outer shell surface (outer surface) 3... Bracket 31... Core connection portion 310... Bottom wall portion 310a... Outer bottom surface of bracket (outer bottom surface) 311... First side wall portion 312... Second side wall portion 313... Bent rounded portion 32... Engine connection portion 7... Spacer 71... Upper surface of spacer (one side surface) 72... Lower surface of spacer (the other side surface) S1... Bonding area (brazing area) S2... Bonding area (brazing area)

Claims

1. a core in which a fluid passage through which a fluid flows and a cooling passage through which a coolant flows are disposed adjacent to each other inside an exterior made of a thin plate, and which enables cooling of the fluid by heat exchange; A bracket is formed by bending a metal plate, and has a curved radius portion that is curved in an arc shape from a bottom wall portion to a side wall portion, and an outer bottom surface of the bottom wall portion is brazed to an outer surface of the thin plate; a spacer having a plate shape having a thickness greater than that of the thin plate, one side surface in the thickness direction being brazed to the outer bottom surface of the bracket, and the other side surface in the thickness direction being brazed to the outer surface of the thin plate; A heat exchanger comprising:

2. 2. The heat exchanger of claim 1, a brazing area between the other side surface of the spacer and the outer side surface of the thin plate is larger than a brazing area between the outer bottom surface of the bracket and the one side surface of the spacer; A heat exchanger comprising:

3. The heat exchanger according to claim 1 is an EGR cooler formed in a square tube shape having a plurality of side surfaces made of the thin plate on an outer periphery of the core, The bracket is brazed to a single surface of the side surface of the core via the spacer. A heat exchanger comprising:

4. 2. The heat exchanger of claim 1, The thin plate, the bracket, and the spacer are all made of stainless steel. A heat exchanger comprising:

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