Heat exchanger

Abstract

A heat exchanger according to the present invention comprises: a body part that includes a heat exchange unit which performs heat exchange between a cooling fluid and a cooling target fluid; a flange that has an inflow port into which the cooling target fluid flows and an outflow port from which the cooling target fluid having flowed through the body part flows out; a first pipe into which the cooling fluid flows; and a second pipe from which the cooling fluid having flowed through the body part flows out. The flange, the first pipe, and the second pipe are bonded to the body part by brazing. In at least one of the flange, the first pipe, and the second pipe, a groove is formed between a portion that is bonded by brazing and a portion that should not be brazed. A flow prevention material that prevents a flow of a molten brazing material is formed in the groove.

Description

Heat exchanger

[0001] The present disclosure relates to a heat exchanger.

[0002] Patent Document 1 provides a groove when brazing a flange or a bracket to a heat exchanger body so that the melted brazing material does not enter around the bolt holes of the bracket or the flange. However, especially when the wettability of the brazing material is high or the groove is shallow, the melted brazing material may spread beyond the groove. Therefore, it is necessary to ensure a certain distance between the brazed part and the parts where brazing is not desired, such as the bolt holes of the bracket or the flange.

[0003] Japanese Patent Application Laid-Open No. 2019-27666

[0004] An object of the present disclosure is to provide a heat exchanger that prevents the melted brazing material from entering parts where brazing is not desired while preventing enlargement.

[0005] A heat exchanger according to an aspect for achieving the above object includes a main body portion including a heat exchange portion that exchanges heat between a cooling fluid and a fluid to be cooled, a flange having an inlet through which the fluid to be cooled flows in and an outlet through which the fluid to be cooled flowing through the main body portion flows out, a first pipe through which the cooling fluid flows in, and a second pipe through which the cooling fluid flowing through the main body portion flows out. The flange, the first pipe, and the second pipe are joined to the main body portion by brazing. In at least one of the flange, the first pipe, and the second pipe, a groove is formed between a portion joined by brazing and a portion where brazing is not desired. A flow prevention material for preventing the flow of the melted brazing material is formed in the groove.

[0006] According to the present disclosure, it is possible to provide a heat exchanger that prevents the melted brazing material from entering parts where brazing is not desired while preventing enlargement.

[0007] It is a front perspective view illustrating the configuration of the EGR cooler according to the present embodiment. It is a rear perspective view of the inlet / outlet header. It is a left side view of the inlet / outlet header. It is an enlarged view of the upper part of the inlet / outlet header in FIG. 3. It is a front perspective view illustrating the configuration of the EGR cooler according to the modified example.

[0008] The embodiments will be described in detail below with reference to the attached drawings. In the drawings used in the following description, the scale has been appropriately changed to make each element recognizable. In the drawings, arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the backward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. These directions are relative directions set for the EGR cooler 10 shown in Figure 1.

[0009] Figure 1 is a front perspective view illustrating the configuration of an EGR (Exhaust Gas Recirculation) system used according to this embodiment. The EGR cooler 10 is a device for cooling exhaust gas. The EGR cooler 10 has passages through which exhaust gas and coolant flow. The exhaust gas is cooled by heat exchange between the exhaust gas and coolant flowing through each passage within the EGR cooler 10. The EGR cooler 10 is an example of a heat exchanger according to this disclosure. Exhaust gas is an example of a fluid to be cooled according to this disclosure. Coolant is an example of a cooling fluid according to this disclosure.

[0010] Specifically, as illustrated in Figure 1, the EGR cooler 10 comprises an inlet / outlet header 11, a shell 12, a duct section 13, a connecting header 14, an inlet pipe 15, and an outlet pipe 16. The inlet / outlet header 11, shell 12, duct section 13, connecting header 14, inlet pipe 15, and outlet pipe 16 are made of, for example, stainless steel or steel.

[0011] The inlet / outlet header 11 is configured to have a first opening 111 and a second opening 112. The first opening 111 is an opening through which exhaust gas flows in. The second opening 112 is an opening through which exhaust gas cooled inside the EGR cooler 10 flows out. The inlet / outlet header 11 corresponds to the flange of this disclosure. The first opening 111 corresponds to the inlet of this disclosure. The second opening 112 corresponds to the outlet of this disclosure.

[0012] Other equipment and other components (hereinafter referred to as "other parts"), not shown in the figures, are attached to the front surface 113 of the entrance / exit header 11. Specifically, with a gasket sandwiched between the front surface 113 of the entrance / exit header 11 and the other parts, the other parts are fastened and secured to the front surface 113 of the entrance / exit header 11 with bolts.

[0013] The shell 12 is formed in a rectangular tubular shape and is configured to surround a heat exchange section 20 that performs heat exchange between exhaust gas flowing into the shell 12 from the inlet / outlet header 11 and coolant flowing into the shell 12 from the inlet pipe 15. The heat exchange section 20 has a first section 21 and a second section 22.

[0014] Part 21 forms a passage through which exhaust gas flows in a first direction. In this example, the first direction is to the right, from the inlet / outlet header 11 to the connecting header 14. Part 21 contains multiple flat tubes (not shown) stacked vertically. Each tube has an inner fin (not shown) inserted inside it. Exhaust gas that flows in from the inlet / outlet header 11, passes through the duct section 13, and is supplied to the shell 12 passes through the inside of the multiple tubes in Part 21.

[0015] The second section 22 forms a passage through which exhaust gas flows in a second direction. The second direction is opposite to the first direction. In this example, the second direction is to the left, from the connecting header 14 toward the inlet / outlet header 11. The second section 22 has multiple flat tubes (not shown) stacked vertically. Each tube has an inner fin (not shown) inserted inside it. The exhaust gas supplied to the shell 12 after passing through the connecting header 14 passes through the inside of the multiple tubes in the second section 22.

[0016] The duct section 13 is configured to connect the inlet / outlet header 11 and the shell 12. The direction of the exhaust gas flow path is changed by the duct section 13 so that the exhaust gas flowing in from the rear of the inlet / outlet header 11 flows into the shell 12 to the right. The duct section 13 is joined to the rear surface 114 (see Figure 2) of the inlet / outlet header 11 by brazing. The duct section 13 is joined to the shell 12 by brazing.

[0017] The duct section 13 has a partition plate 131. The partition plate 131 is provided inside the duct section 13. The partition plate 131 divides the inside of the duct section 13 into a first passage 132 and a second passage 133. The first passage 132 connects the first opening 111 of the inlet / outlet header 11 to a part 21 of the heat exchange section 20. The second passage 133 connects the second opening 112 of the inlet / outlet header 11 to a part 22 of the heat exchange section 20. The duct section 13, together with the shell 12, constitutes the main body of the present disclosure.

[0018] The connecting header 14 is connected to the shell 12. The connecting header 14 is joined to the shell 12 by brazing. The connecting header 14 is configured to close the end of the shell 12 and connect the first part 21 and the second part 22 of the heat exchange section 20.

[0019] The inlet pipe 15 is connected to the shell 12 and communicates with the second section 22. The inlet pipe 15 is joined to the shell 12 by brazing. The inlet pipe 15 is connected to, for example, a supply pipe of a coolant tank (not shown). The coolant from the coolant tank flows in through the inlet pipe 15 and is supplied to the inside of the shell 12. The inlet pipe 15 corresponds to the first pipe in this disclosure.

[0020] The outlet pipe 16 is connected to the shell 12 and communicates with the first part 21. The outlet pipe 16 is joined to the shell 12 by brazing. The outlet pipe 16 is connected, for example, to the recovery pipe of a coolant recovery tank. The coolant inside the shell 12 is discharged from the outlet pipe 16 and recovered into the coolant recovery tank. The outlet pipe 16 corresponds to the second pipe in this disclosure.

[0021] In the EGR cooler 10 configured in this way, exhaust gas flowing in from the first opening 111 of the inlet / outlet header 11 passes through the first passage 132 of the duct section 13, flows through a tube located in the first part 21 of the heat exchange section 20 of the shell 12, makes a U-turn at the connecting header 14, flows through a tube located in the second part 22 of the heat exchange section 20, passes through the second passage 133 of the duct section 13, and flows out from the second opening 112 of the inlet / outlet header 11. Coolant supplied to the inside of the shell 12 from the inlet pipe 15 flows between the outside of the tube and the shell 12 and flows out from the outlet pipe 16. The exhaust gas passing through the tube is cooled by the coolant flowing around the tube.

[0022] When manufacturing the EGR cooler 10, brazing material is applied to the joints of the components, and the components are temporarily assembled. The temporarily assembled products are then brazed together in a furnace to join the components. During this brazing process, if molten brazing material adheres to parts of the components to which other parts are attached, it will affect the accuracy of the attachment. For example, if excess brazing material flows from the joint between the rear surface 114 of the inlet / outlet header 11 and the duct section 13 onto the front surface 113 of the inlet / outlet header 11, it will affect the attachment to other parts.

[0023] In contrast, the EGR cooler 10 of this disclosure has a groove 17 formed between the front surface 113 and the rear surface 114 of the inlet / outlet header 11 where the duct portion 13 is joined, in order to prevent molten brazing material from flowing into the front surface 113 of the inlet / outlet header 11 during brazing, and a flow-preventing material 18 is formed in the groove 17 to prevent the flow of molten brazing material.

[0024] The grooves 17 and flow prevention material 18 formed in the inlet / outlet header 11 will be described in detail below with reference to Figures 2 to 4. Figure 2 is a rear perspective view of the inlet / outlet header 11. Figure 3 is a left side view of the inlet / outlet header 11. Figure 4 is an enlarged view of the upper part of the inlet / outlet header 11 in Figure 3. In Figure 2, hatching is applied to the area 114A where the duct portion 13 of the rear surface 114 is joined. In Figure 3, dashed lines indicate other parts attached to the inlet / outlet header 11. In Figure 4, hatching is applied to the flow prevention material 18.

[0025] As illustrated in Figure 2, a groove 17 is formed on the outer peripheral surface 115 between the front surface 113 and the rear surface 114 of the entrance / exit header 11. In this example, the groove 17 is formed around the entire circumference of the outer peripheral surface 115.

[0026] As described above, the front surface 113 is a part to which other parts are attached and is a part that should not be brazed. The area 114A of the rear surface 114 to which the duct portion 13 is joined is a part that is joined by brazing. In other words, in the entrance / exit header 11, a groove 17 is formed between the part that is joined by brazing and the part that should not be brazed.

[0027] Furthermore, as illustrated in Figure 3, the front portion of the outer circumferential surface 115 of the entrance / exit header 11 engages with the claw portion 101 of another component 100. In other words, the front portion of the outer circumferential surface 115 of the entrance / exit header 11 is the part to which other components are attached and is a part that should not be brazed. Therefore, in this example, the groove 17 is provided on the rear portion of the outer circumferential surface 115 of the entrance / exit header 11.

[0028] As illustrated in Figure 4, the groove 17 is provided with a flow-preventing material 18 to prevent the flow of molten brazing material. For example, when nickel (Ni) is used as the brazing material, titanium oxide is used as the flow-preventing material 18. When an organic solvent containing titanium oxide is applied to the groove 17 and brazing is performed, the titanium oxide remains in the groove 17 as the flow-preventing material 18.

[0029] Now, let's consider the case where either a groove 17 or a flow-preventing material 18 is formed on the outer circumferential surface 115 of the inlet / outlet header 11. If only a groove 17 is formed on the outer circumferential surface 115 of the inlet / outlet header 11, for example, if the brazing material has high wettability or the groove is shallow, the molten brazing material may flow over the groove 17 during brazing and onto the front surface 113 of the inlet / outlet header 11. On the other hand, if only a flow-preventing material 18 is formed on the outer circumferential surface 115 of the inlet / outlet header 11, if there are any gaps in the application of the flow-preventing material 18 or if the flow-preventing material 18 is interrupted, the molten brazing material may flow out from there.

[0030] In contrast, the EGR cooler 10 of this disclosure uses both grooves 17 and flow-preventing material 18, so even if the brazing material has high wettability or the grooves are shallow, the flow of molten brazing material can be blocked by the flow-preventing material 18. Alternatively, even if the flow-preventing material 18 is not applied properly or is interrupted, the flow of molten brazing material can be blocked by the grooves 17. In other words, by using both grooves 17 and flow-preventing material 18, it is possible to prevent molten brazing material from flowing from the joint between the rear surface 114 of the inlet / outlet header 11 and the duct section 13 onto the front surface 113 of the inlet / outlet header 11 during brazing.

[0031] Furthermore, the organic solvent that serves as the flow-preventing material 18 is applied by an operator using, for example, a pen-type applicator. For example, if there is no groove 17, skilled technique is required to apply the flow-preventing material 18 to the correct position. In particular, since the inlet / outlet header 11 is thin, it is difficult to apply the flow-preventing material 18 to the narrow outer surface 115. For example, although using a jig makes it easier to apply the flow-preventing material 18 to the correct position, the flow-preventing material 18 adhering to the jig may come into contact with unintended areas, causing the brazing material to adhere to them.

[0032] In contrast, with the EGR cooler 10 of this disclosure, since the flow-preventing material 18 is applied inside the groove 17, even when applying the flow-preventing material 18 to a narrow area such as the outer surface 115 of the inlet / outlet header 11, the flow-preventing material 18 can be accurately applied to the desired position without using a jig.

[0033] In this example, the groove 17 is formed over the entire circumference of the outer surface 115 of the inlet / outlet header 11, but it may also be formed over a portion of the outer surface 115. For example, on the outer surface 115 of the inlet / outlet header 11, the groove 17 can be formed in a portion where excess brazing material is likely to flow from the joint between the rear surface 114 of the inlet / outlet header 11 and the duct portion 13, and a flow-preventing material 18 can be formed in the groove 17. This prevents molten brazing material from flowing onto the front surface 113 of the inlet / outlet header 11.

[0034] Furthermore, the groove 17 and the flow prevention material 18 are provided on the rear portion of the outer circumferential surface 115 of the inlet / outlet header 11. However, if, for example, there are no other parts to engage with the front portion of the outer circumferential surface 115, the groove 17 may be provided on the front portion of the outer circumferential surface 115.

[0035] Figure 5 is a front perspective view illustrating the configuration of an EGR cooler 30 according to a modified example. Components that are substantially the same as those of the EGR cooler 10 according to the above embodiment are given the same reference numerals, and redundant explanations are omitted.

[0036] As illustrated in Figure 5, grooves 17 and flow-preventing material 18 are formed on the outer circumferential surface 115 of the inlet / outlet header 11.

[0037] Furthermore, a groove 17 is formed between the tip 152 into which the coolant flows in the inlet pipe 15 and the portion that is joined to the shell 12. In this example, the groove 17 is formed around the entire circumference of the outer surface 151 of the inlet pipe 15.

[0038] The tip 152 of the inlet pipe 15 is the part to which the coolant tank supply pipe is attached, as described above, and is a part that should not be brazed. The part of the inlet pipe 15 that is joined to the shell 12 is a part that is joined by brazing. In other words, a groove 17 is formed in the inlet pipe 15 between the part that is joined by brazing and the part that should not be brazed.

[0039] Furthermore, a groove 17 and a flow-preventing material 18 are also formed between the tip 162 from which the coolant flows out of the outlet pipe 16 and the portion that is joined to the shell 12. In this example, the groove 17 is formed around the entire circumference of the outer surface 161 of the outlet pipe 16.

[0040] The tip 162 of the outlet pipe 16 is the part to which the coolant recovery pipe of the coolant recovery tank is attached, as described above, and is a part that should not be brazed. The part of the outlet pipe 16 that is joined to the shell 12 is a part that is joined by brazing. In other words, a groove 17 is formed in the outlet pipe 16 between the part that is joined by brazing and the part that should not be brazed.

[0041] On the outer peripheral surfaces 151 of the inlet pipe 15 and 161 of the outlet pipe 16, a flow prevention material 18 for preventing the flow of the molten brazing material is formed in the groove 17 formed thereon.

[0042] According to the EGR cooler 30 of the modification, by using both the groove 17 and the flow prevention material 18, it is possible to prevent the molten brazing material from flowing from the joint portion between the shell 12 and the inlet pipe 15 into the tip portion 152 of the inlet pipe 15 during brazing. Further, it is possible to prevent the molten brazing material from flowing from the joint portion between the shell 12 and the outlet pipe 16 into the tip portion 162 of the outlet pipe 16 during brazing.

[0043] Also, when applying an organic solvent as the flow prevention material 18, since the inlet pipe 15 and the outlet pipe 16 are cylindrical, it is difficult to apply the flow prevention material 18. However, according to the EGR cooler 30 of the modification, since the groove 17 is first formed on the outer peripheral surface 151 of the inlet pipe 15 and the outer peripheral surface 161 of the outlet pipe 16, and the flow prevention material 18 is applied to the groove 17, the flow prevention material 18 can be accurately applied to the desired position without using a jig.

[0044] Note that the position where the groove 17 is formed in the inlet pipe 15 and the outlet pipe 16 is not limited to this example.

[0045] Also, although the groove 17 and the flow prevention material 18 are respectively formed in the inlet pipe 15 and the outlet pipe 16, they may be formed on the outer peripheral surface of either one of the inlet pipe 15 and the outlet pipe 16. For example, depending on the posture of the assembled product during brazing, there is a direction in which the excess brazing material easily flows. Therefore, the groove 17 and the flow prevention material 18 may be formed on the side where the excess brazing material easily flows to the tip portion among the inlet pipe 15 and the outlet pipe 16.

[0046] Also, although the groove 17 and the flow prevention material 18 are formed in the inlet / outlet header 11, the inlet pipe 15, and the outlet pipe 16, the groove 17 and the flow prevention material 18 may be formed in at least any one of them.

[0047] Furthermore, the EGR cooler 30 of this modification example includes a bracket 19. A bolt hole 191 is formed in the bracket 19, and the bracket 19 is fastened and fixed to other components by bolts not shown. The bracket 19 is joined to the shell 12 by brazing.

[0048] In the bracket 19, a groove 17 is formed between the bolt hole 191 and a portion 193 where the shell 12 is joined. In this example, the groove 17 is formed in the front surface 192 of the bracket 19. The bracket 19 is formed such that the minimum distance L1 between the portion 193 where the bolt hole 191 and the shell 12 are joined is less than 20 mm.

[0049] The bolt hole 191 is a portion through which the bolt passes and is a portion where brazing is not desired. The portion 193 where the shell 12 is joined is a portion joined by brazing. That is, a groove 17 is formed between the portion joined by brazing and the portion where brazing is not desired.

[0050] A flow prevention material 18 for preventing the flow of the molten brazing material is formed in the groove 17.

[0051] According to such a configuration, by using both the groove 17 and the flow prevention material 18, it is possible to prevent the molten brazing material from entering the bolt hole 191 from the joint portion between the shell 12 and the bracket 19 during brazing. Thereby, the minimum distance L1 between the bolt hole 191 of the bracket 19 and the portion 193 where the shell 12 is joined can be shortened. Therefore, it is possible to prevent the molten brazing material from entering the bolt hole 191 while preventing the bracket 19 from becoming larger.

[0052] Note that the position where the groove 17 is formed in the front surface 192 of the bracket 19 is not limited to this example. Also, the groove 17 and the flow prevention material 18 may be formed on the rear surface of the bracket 19.

[0053] The above embodiments are merely examples for facilitating the understanding of the present invention. The configurations according to the above embodiments can be appropriately changed and improved without departing from the gist of the present invention.

[0054] In the above embodiments and modifications, the EGR coolers 10 and 30 have a duct section 13, but the duct section 13 may be omitted. In this case, the shell 12 constitutes the main body of the disclosure, and the inlet / outlet header 11 is directly joined to the shell 12 by brazing.

[0055] In the above embodiments and modifications, the EGR coolers 10 and 30 are of the U-turn type, in which exhaust gas flows in and out from an inlet / outlet header 11 provided at one end of the shell 12, and the exhaust gas flowing inside the shell 12 is returned by a connecting header 14 provided at the other end of the shell 12. However, the EGR coolers 10 and 30 may also be of the linear type, in which the exhaust gas flowing inside the shell 12 proceeds in a straight line. A linear EGR cooler has an inlet header provided at one end of the shell 12 and having an inlet for the exhaust gas, and an outlet header provided at the other end of the shell and having an outlet for the exhaust gas. In this case, the groove 17 and the flow prevention material 18 may be provided on one or both of the inlet header and the outlet header.

[0056] In the embodiments and modifications described above, an example of a part that should not be brazed was given as a part to which other parts are attached, but this is not limited to that.

[0057] In the above embodiments and modifications, the EGR coolers 10 and 30 are configured so that exhaust gas flows from top to bottom inside the EGR coolers 10 and 30, but they may also be configured so that the exhaust gas flows from bottom to top.

[0058] In the embodiments and modifications described above, an EGR cooler for cooling exhaust gas was described as an example of a heat exchanger. However, the heat exchanger may also be one that cools a fluid other than exhaust gas.

[0059] The configurations described in each of the following items also constitute part of this disclosure. Item 1: A heat exchanger comprising: a main body including a heat exchange section for performing heat exchange between a cooling fluid and a fluid to be cooled; a flange having an inlet for the fluid to be cooled to flow in and an outlet for the fluid to be cooled that has flowed through the main body to flow out; a first pipe for the cooling fluid to flow in; and a second pipe for the cooling fluid that has flowed through the main body to flow out, wherein the flange, the first pipe, and the second pipe are joined to the main body by brazing; a groove is formed between the brazed portion and the portion that is not to be brazed in at least one of the flange, the first pipe, and the second pipe; and a flow-preventing material is formed in the groove to prevent the flow of molten brazing material. Item 2: The heat exchanger according to Item 1, wherein the groove is provided around the entire circumference of the outer surface of the flange. Item 3: The heat exchanger according to Item 1 or Item 2, wherein the groove is provided around the entire circumference of the outer surface of at least one of the first pipe and the second pipe. Item 4: A heat exchanger according to any one of items 1 to 3, having a bracket joined to the main body by brazing, wherein a groove is formed between the brazed portion and the portion that is not to be brazed, the groove contains a flow-preventing material to prevent the flow of molten brazing material, and the minimum distance between the brazed portion and the portion that is not to be brazed is less than 20 mm.

[0060] This application is based on Japanese Patent Application No. 2024-195783, filed on 8 November 2024, the contents of which are incorporated herein by reference.

Claims

1. A heat exchanger comprising: a main body including a heat exchange section for performing heat exchange between a cooling fluid and a fluid to be cooled; a flange having an inlet for the fluid to be cooled to flow in and an outlet for the fluid to be cooled that has flowed through the main body to flow out; a first pipe for the cooling fluid to flow in; and a second pipe for the cooling fluid that has flowed through the main body to flow out, wherein the flange, the first pipe, and the second pipe are joined to the main body by brazing; a groove is formed between the brazed portion and the portion that is not to be brazed in at least one of the flange, the first pipe, and the second pipe; and a flow-preventing material is formed in the groove to prevent the flow of molten brazing material.

2. The heat exchanger according to claim 1, wherein the groove is provided around the entire circumference of the outer surface of the flange.

3. The heat exchanger according to claim 1 or 2, wherein the groove is provided around the entire circumference of at least one of the outer surfaces of the first pipe and the second pipe.

4. The heat exchanger according to claim 1 or claim 2, which has a bracket joined to the main body by brazing, wherein a groove is formed between the brazed portion and the portion that is not to be brazed, the groove contains a flow-preventing material to prevent the flow of molten brazing material, and the minimum distance between the brazed portion and the portion that is not to be brazed is less than 20 mm.

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