Heat exchanger and method for manufacturing heat exchanger

Abstract

This heat exchanger comprises a first member and a second member joined by laser welding, and a fluid flow channel formed between the first member and the second member. The second member has a rib that is joined to the first member by laser welding and partitions the flow channel. A rib welding bead for joining the rib to the first member has a circular arc part formed in a circular arc shape at an end portion thereof. The joining depth decreases toward the tip end of the circular arc part, which is the start point or the end point of the laser welding. In the path of the rib welding bead, the preceding bead and the following bead do not overlap, or the joining depth at the tip end of the circular arc part is such that the first member and the second member are not joined.

Description

Heat exchanger and method for manufacturing the same

[0001] The present invention relates to a heat exchanger and a method for manufacturing a heat exchanger.

[0002] WO2014 / 162980A1 discloses a temperature adjustment device for a storage battery that includes a heating unit in which an upper surface and a lower surface are joined by brazing.

[0003] When joining components together by brazing, such as in the heating unit (heat exchanger) described above, a heating furnace for brazing is generally provided in the mass production process. However, for example, if the size of the heating unit is large, the heating furnace must also be enlarged accordingly, making it difficult to improve production efficiency.

[0004] Therefore, instead of brazing, it is conceivable to join the members together by laser welding, but in this case, stress concentration tends to occur around the weld bead due to the internal pressure of the heated part.

[0005] The present invention has been made in consideration of the above problems, and has an object to ensure the strength of a heat exchanger manufactured using laser welding.

[0006] According to one aspect of the present invention, there is provided a heat exchanger comprising a first member and a second member joined by laser welding, and a fluid flow path formed between the first member and the second member, wherein the second member has a rib that is joined to the first member by the laser welding and separates the flow path, and the rib weld bead that joins the rib to the first member has an arc portion formed in an arc shape at its end, and the joining depth becomes shallower toward the tip of the arc portion, which is the start or end point of the laser welding, and the leading bead and the trailing bead do not overlap in the trajectory of the rib weld bead, or the joining depth at the tip of the arc portion is deep enough that the first member and the second member are not joined.

[0007] According to the above-described aspect, the end of the rib weld bead, where stress concentration due to the internal pressure of the heat exchanger is likely to occur, is formed into an arc-shaped portion, thereby suppressing stress concentration at the end of the rib weld bead. Furthermore, by making the joining depth shallow at the tip of the arc portion, i.e., the start and end points of the laser welding, the heat input can be optimized, improving welding quality. Furthermore, if the leading bead and the trailing bead are prevented from overlapping in the trajectory of the rib weld bead, the trailing bead can be prevented from affecting the joining strength of the leading bead. The same applies when the joining depth at the tip of the arc portion is set to a depth that does not join the first and second members. Even if the tip of the arc portion overlaps the leading bead, the joining strength of the leading bead can be prevented from being affected. Therefore, according to the above-described aspect, the strength of the heat exchanger manufactured using laser welding can be ensured.

[0008] FIG. 1 is a side view showing a state in which a heat exchanger according to an embodiment of the present invention is mounted on a vehicle. FIG. 2 is a top view showing a state in which a heat exchanger according to an embodiment of the present invention is mounted on a vehicle. FIG. 3 is a top view showing an example of a heat exchanger. FIG. 4 is a bottom view showing an example of a heat exchanger. FIG. 5 is a V-V cross-sectional view of FIG. 3. FIG. 6 is a VI-VI cross-sectional view of FIG. 3. FIG. 7 is a diagram for explaining the joining depth of a rib weld bead. FIG. 8 is a diagram showing a rib weld bead according to a first modified example. FIG. 9 is a diagram showing a rib weld bead according to a second modified example. FIG. 10 is a diagram for explaining the joining depth of a rib weld bead according to the second modified example. FIG. 11 is a diagram showing a rib weld bead according to a third modified example.

[0009] A heat exchanger 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same components are denoted by the same reference numerals.

[0010] Fig. 1 is a side view showing a state in which the heat exchanger 100 is mounted on a vehicle 200. Fig. 2 is a top view showing a state in which the heat exchanger 100 is mounted on the vehicle 200.

[0011] As shown in FIGS. 1 and 2, the heat exchanger 100 is attached to a vehicle 200 as an external device by a plurality of bolts 110.

[0012] The battery 120 is stacked on the heat exchanger 100. The battery 120 is maintained stacked on the heat exchanger 100 by attaching a mounting member 130 attached from above the battery 120 to the vehicle 200 with bolts 110. The heat exchanger 100 may also be stacked on the battery 120.

[0013] The heat exchanger 100 is connected to a fluid supply pipe 140 that supplies a fluid for heat exchange to the heat exchanger 100, and a fluid discharge pipe 150 that discharges the fluid from the heat exchanger 100. The fluid for heat exchange is, for example, water.

[0014] By supplying the heat exchanger 100 with a fluid having a higher temperature than the batteries 120, it is possible to heat the batteries 120 stacked in the heat exchanger 100. In addition, by supplying the heat exchanger 100 with a fluid having a lower temperature than the batteries 120, it is possible to cool the batteries 120 stacked in the heat exchanger 100.

[0015] Next, the heat exchanger 100 will be described.

[0016] Fig. 3 is a top view showing an example of the heat exchanger 100. Fig. 4 is a bottom view showing an example of the heat exchanger 100. Fig. 5 is a cross-sectional view taken along line VV in Fig. 3. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 3.

[0017] 3 and 4, the heat exchanger 100 includes a first member 10 and a second member 20. The first member 10 and the second member 20 are made of, for example, an aluminum alloy.

[0018] The first member 10 and the second member 20 are joined by laser welding. In Fig. 3, the back bead of the laser welding is shown by a dotted line. In Fig. 4, the front bead of the laser welding is shown by a thick solid line. That is, in this embodiment, laser welding is performed from the second member 20 side. However, laser welding may also be performed from the first member 10 side.

[0019] The first member 10 is flat and has a fluid supply port 11 formed at one end and a fluid discharge port 12 formed at the other end. A fluid supply pipe 140 is connected to the fluid supply port 11. A fluid discharge pipe 150 is connected to the fluid discharge port 12.

[0020] The second member 20 has a flange 21 that abuts against the first member 10, a recess 22 that forms a fluid flow path 27 between the second member 20 and the first member 10, a plurality of ribs 23 that are formed in the recess 22 and abut against the first member 10, and a plurality of protrusions 24 that extend from the flange 21 toward the outside of the heat exchanger 100. Holes 25 are formed in the protrusions 24. The protrusions 24 form mounting portions for mounting the heat exchanger 100 to the vehicle 200 with bolts 110.

[0021] The flange 21 is joined to the first member 10 by laser welding. The shape of the flange 21 is formed to follow the outer shape of the first member 10. Therefore, when the flange 21 and the first member 10 are joined by laser welding, a peripheral weld bead 26 is formed that joins the outer periphery of the heat exchanger 100 so as to surround the fluid supply port 11 and the fluid discharge port 12. As a result, a fluid flow path 27 is formed between the first member 10 and the second member 20.

[0022] 4 , two ends 261 of circumferential weld bead 26 are located on protrusion 24 (mounting portion). That is, two ends 261 of circumferential weld bead 26 are located away from flow path 27. Therefore, stress concentration on two ends 261 of circumferential weld bead 26 due to the internal pressure of heat exchanger 100 can be suppressed.

[0023] Furthermore, in this embodiment, the start and end points of outer periphery weld bead 26 are positioned further outward from heat exchanger 100 than the center of hole 25 formed in protrusion 24, i.e., further away from flow path 27 than the center of hole 25. This makes it possible to suppress stress concentration at the start and end points of outer periphery weld bead 26 due to the internal pressure of heat exchanger 100.

[0024] As shown in FIGS. 4 and 5 , each of the plurality of ribs 23 has a flat portion 231 that abuts against the first member 10 and a wall portion 232 that rises from the flat portion 231 .

[0025] The flat portion 231 of each of the plurality of ribs 23 is joined to the first member 10 by laser welding. The plurality of ribs 23 divide the flow path 27, thereby rectifying the flow of the fluid flowing through the flow path 27.

[0026] As shown in FIG. 4 , the rib weld bead 28 formed on the rib 23 by laser welding has a straight portion 281 along the longitudinal direction of the rib 23 and two arc portions 282 formed in an arc shape at both ends of the straight portion 281.

[0027] As shown in FIGS. 4 and 5, the straight portion 281 is formed at the center of the rib 23 in the width direction.

[0028] Therefore, the internal pressure of the heat exchanger 100 acts evenly on the straight portion 281 from both sides of the rib 23. This allows the stress generated around the straight portion 281 to be evenly dispersed on both sides of the straight portion 281. In other words, by forming the straight portion 281 at the center of the rib 23 in the width direction, stress concentration on the straight portion 281 can be suppressed.

[0029] 4, the arc portion 282 is formed along the arc shape of the end portion of the rib 23. Specifically, the arc portion 282 in this embodiment is formed on the circumference.

[0030] In this way, by making the ends of the rib weld bead 28, where stress concentration due to the internal pressure of the heat exchanger 100 is likely to occur, into arc-shaped arc portions 282, stress concentration at the ends of the rib weld bead 28 can be suppressed.

[0031] As shown in FIG. 6 , the arc portion 282 is formed on the flat portion 231 along the end of the R of the curved surface connecting the flat portion 231 and the wall portion 232 of the rib 23 .

[0032] This reduces the pressure-receiving area of ​​the flat portion 231 around the arc portion 282, thereby reducing the stress generated around the arc portion 282.

[0033] In addition, the rib weld bead 28 has an upslope / downslope at the tip of the arc portion 282, making the joining depth shallower.

[0034] In this way, by making the joining depth shallow at the tip of the arc portion 282, that is, at the start and end points of the laser welding, the amount of heat input can be made appropriate, and the welding quality can be improved.

[0035] 7 is a diagram for explaining the joining depth of the rib weld bead 28. In FIG. 7, the joining depth at points A to E shown in FIG.

[0036] 7, the section of rib weld bead 28 from point A to point D has a predetermined joint depth that exceeds the plate thickness of second member 20. The joint depth becomes shallower from point D to point E. Point E is the tip of rib weld bead 28. Note that point E may be the start point or the end point of rib weld bead 28.

[0037] 4, point D is a position where the circle described by arc portion 282 exceeds a semicircle and where a tangent to arc portion 282 is parallel to the longitudinal direction of rib 23. In other words, point D is a point where the orientation of rib weld bead 28 is opposite to the direction in which rib 23 extends toward the end portion.

[0038] In this way, by keeping the joining depth shallow until the arc portion 282 forms at least a semicircle and extending beyond the semicircle toward the tip end where the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23, it is possible to improve the pressure resistance at the end of the rib 23, where stress is likely to concentrate.

[0039] In this embodiment, as shown in Fig. 4, points E and B are at the same position. That is, in the trajectory of rib weld bead 28, the leading end (point E) of rib weld bead 28, which is the trailing bead, overlaps with the middle portion (point B) of rib weld bead 28, which is the leading bead. In other words, the leading bead and the trailing bead overlap in the trajectory of rib weld bead 28.

[0040] In contrast, as shown in FIG. 6, the joining depth of the rib weld bead 28 between points D and E is shallow enough that the first member 10 and the second member 20 are not joined.

[0041] This prevents the leading edge of the arc portion 282 from overlapping the leading bead, as in this embodiment, from affecting the joining strength of the leading bead.

[0042] Next, a rib weld bead 28 according to a first modified example will be described with reference to FIG.

[0043] FIG. 8 is a diagram showing a rib weld bead 28 according to a first modified example.

[0044] As shown in FIG. 8, the rib weld bead 28 of the first modified example differs from the rib weld bead 28 shown in FIG. 4 in that it has an arc-shaped connecting portion 283 that connects a straight portion 281 and an arc portion 282.

[0045] In this way, by forming the connecting portion 283 connecting the straight portion 281 and the arc portion 282 in an arc shape, it is possible to suppress a local increase in the laser input at the connecting portion 283. Therefore, it is possible to improve the welding quality.

[0046] Furthermore, in the rib weld bead 28 of the first modified example, point B is spaced apart from point E. In other words, the leading bead and the trailing bead do not overlap in the trajectory of the rib weld bead 28.

[0047] This prevents the trailing bead from affecting the joining strength of the leading bead.

[0048] Next, a rib weld bead 28 according to a second modified example will be described with reference to FIG.

[0049] FIG. 9 is a diagram showing a rib weld bead 28 according to a second modified example.

[0050] As shown in FIG. 9, the rib weld bead 28 of the second modified example differs from the rib weld bead 28 shown in FIG. 4 in that the tip (point E') of the rib weld bead 28 is spaced apart from point B.

[0051] That is, in the rib weld bead 28 of the second modified example, the leading bead and the trailing bead do not overlap in their trajectory.

[0052] This prevents the trailing bead from affecting the joining strength of the leading bead.

[0053] FIG. 10 is a diagram for explaining the joining depth of the rib weld bead 28 according to the second modified example.

[0054] As can be seen from Figures 9 and 10, the rib weld bead 28 according to the second modified example has an arc portion 282 that forms at least a semicircle, and the joining depth is not made shallower until it exceeds the semicircle and extends toward the tip end to a position (point D) where the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23.

[0055] This improves the pressure resistance at the end of the rib 23 where stress tends to concentrate.

[0056] Next, a rib weld bead 28 according to a third modified example will be described with reference to Fig. 11. Fig. 11 is a diagram showing a rib weld bead 28 according to the third modified example.

[0057] As shown in Fig. 11 , rib weld bead 28 of the third modified example differs from rib weld bead 28 shown in Fig. 4 in that a straight line portion 281 is formed at a position that is off the center of rib 23 in the width direction of rib 23. However, other configurations of rib weld bead 28 of the third modified example are the same as those of rib weld bead 28 shown in Fig. 4 .

[0058] Specifically, the rib weld bead 28 of the third modified example has an arc portion 282 formed in an arc shape at its end, and the leading bead and the trailing bead do not overlap in their trajectory.

[0059] The joining depth becomes shallower toward the tip of the arc portion 282, which is the start point or end point of the laser welding (not shown).

[0060] Therefore, according to the third modification, the end of rib weld bead 28, where stress concentration due to the internal pressure of heat exchanger 100 is likely to occur, is formed into arc-shaped portion 282, thereby suppressing stress concentration at the end of rib weld bead 28. Also, because the joint depth is shallow at the tip of arc portion 282, i.e., the start and end points of laser welding, the amount of heat input can be optimized, thereby improving welding quality. Furthermore, because the leading bead and trailing bead do not overlap in the trajectory of rib weld bead 28, the trailing bead is prevented from affecting the joint strength of the leading bead.

[0061] In addition, the rib weld bead 28 of the third modified example is configured so that the arc portion 282 forms at least a semicircle, and the joining depth is not shallowed beyond the semicircle toward the tip end until the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23 (not shown).

[0062] In this way, by keeping the joining depth shallow until the arc portion 282 forms at least a semicircle and extending beyond the semicircle toward the tip end where the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23, it is possible to improve the pressure resistance at the end of the rib 23, where stress is likely to concentrate.

[0063] In addition, in the rib weld bead 28 of the third modified example, the arc portion 282 is formed on the flat portion 231 along the end of the R of the curved surface connecting the flat portion 231 and the wall portion 232 of the rib 23 .

[0064] This reduces the pressure-receiving area of ​​the flat portion 231 around the arc portion 282, thereby reducing the stress generated around the arc portion 282.

[0065] As described above, heat exchanger 100 includes first member 10 and second member 20 joined by laser welding, and fluid flow path 27 is formed between first member 10 and second member 20. Second member 20 has rib 23 joined to first member 10 by laser welding to separate flow path 27, and rib weld bead 28 joining rib 23 to first member 10 has arc portion 282 formed in an arc shape at its end, and the joining depth becomes shallower toward the tip of arc portion 282, which is the start point or end point of the laser welding, so that the leading bead and the trailing bead do not overlap in the trajectory of rib weld bead 28, or the joining depth at the tip of arc portion 282 is deep enough that first member 10 and second member 20 are not joined.

[0066] This configuration allows the end of the rib weld bead 28, where stress concentration due to the internal pressure of the heat exchanger 100 is likely to occur, to be formed into an arc-shaped arc portion 282, thereby suppressing stress concentration at the end of the rib weld bead 28. Furthermore, the joining depth is shallow at the tip of the arc portion 282, i.e., at the start and end points of the laser welding, allowing for appropriate heat input and improving welding quality. Furthermore, if the leading bead and the trailing bead are not overlapped in the trajectory of the rib weld bead 28, the trailing bead is prevented from affecting the joining strength of the leading bead. The same applies when the joining depth at the tip of the arc portion 282 is set to a depth that does not join the first member 10 and the second member 20. Even if the tip of the arc portion 282 overlaps the leading bead, the joining strength of the leading bead is prevented from being affected. Therefore, the strength of the heat exchanger 100 manufactured using laser welding can be ensured.

[0067] Furthermore, the arc portion 282 forms at least a semicircle, and the joining depth does not become shallower beyond the semicircle toward the tip end until the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23.

[0068] In this way, by keeping the joining depth shallow until the arc portion 282 forms at least a semicircle and extending beyond the semicircle toward the tip end where the tangent to the arc portion 282 becomes parallel to the longitudinal direction of the rib 23, it is possible to improve the pressure resistance at the end of the rib 23, where stress is likely to concentrate.

[0069] The rib weld bead 28 also has a linear portion 281 formed in a straight line, and the linear portion 281 extends along the longitudinal direction of the rib 23. The linear portion 281 can be formed in the center of the rib 23 in the width direction.

[0070] This allows stress generated around the straight portion 281 to be evenly distributed to both sides of the straight portion 281. In other words, by forming the straight portion 281 at the center of the rib 23 in the width direction, stress concentration at the straight portion 281 can be suppressed.

[0071] Furthermore, the connecting portion 283 that connects the linear portion 281 and the arc portion 282 may be arc-shaped.

[0072] By forming the connecting portion 283 connecting the straight portion 281 and the arc portion 282 in an arc shape, it is possible to suppress a local increase in the laser input at the connecting portion 283. This makes it possible to improve the welding quality.

[0073] In addition, the rib 23 has a flat portion 231 that abuts against the first member 10 and a wall portion 232 that rises from the flat portion 231, and the arc portion 282 of the rib weld bead 28 is formed along the R end of the curved portion that connects the flat portion 231 and the wall portion 232 of the rib 23.

[0074] This reduces the pressure-receiving area of ​​the flat portion 231 around the arc portion 282, thereby reducing the stress generated around the arc portion 282.

[0075] The heat exchanger 100 also has a mounting portion for mounting to the vehicle 200, and two ends 261 of the outer periphery weld bead 26 that joins the outer periphery are located at the mounting portion. The mounting portion is a protrusion 24 that extends outward from the heat exchanger 100.

[0076] This can suppress stress concentration on the two ends 261 of the outer circumferential weld bead 26 due to the internal pressure of the heat exchanger 100 .

[0077] In addition, in a manufacturing method of a heat exchanger 100 comprising a first member 10 and a second member 20 joined by laser welding, with a fluid flow path 27 formed between the first member 10 and the second member 20, the second member 20 has a rib 23 that is joined to the first member 10 by laser welding and separates the flow path 27, and in the laser welding that forms a rib weld bead 28 that joins the rib 23 to the first member 10, an arc-shaped arc portion 282 is formed at the end of the rib weld bead 28, and the joining depth becomes shallower toward the tip of the arc portion 282, which is the start or end point of the laser welding, so that the leading bead and the trailing bead do not overlap in the trajectory of the rib weld bead 28, or the joining depth at the tip of the arc portion 282 is set to a depth that does not join the first member 10 and the second member 20.

[0078] This configuration allows the end of the rib weld bead 28, where stress concentration due to the internal pressure of the heat exchanger 100 is likely to occur, to be formed into an arc-shaped arc portion 282, thereby suppressing stress concentration at the end of the rib weld bead 28. Furthermore, the joining depth is shallow at the tip of the arc portion 282, i.e., at the start and end points of the laser welding, allowing for appropriate heat input and improving welding quality. Furthermore, if the leading bead and the trailing bead are not overlapped in the trajectory of the rib weld bead 28, the trailing bead is prevented from affecting the joining strength of the leading bead. The same applies when the joining depth at the tip of the arc portion 282 is set to a depth that does not join the first member 10 and the second member 20. Even if the tip of the arc portion 282 overlaps the leading bead, the joining strength of the leading bead is prevented from being affected. Therefore, the strength of the heat exchanger 100 manufactured using laser welding can be ensured.

[0079] Although an embodiment of the present invention has been described above, the above embodiment merely shows one application example of the present invention, and is not intended to limit the technical scope of the present invention to the specific configuration of the above embodiment.

[0080] For example, in the above embodiment, the heat exchanger 100 is used to adjust the temperature of the battery 120. However, the use of the heat exchanger 100 is not limited to this.

[0081] Furthermore, the outer shape of the heat exchanger 100 and the shape and number of the ribs 23 can be changed as appropriate.

[0082] Additionally, the outer circumferential weld bead 26 may be divided into a plurality of beads.

[0083] This application claims priority based on Japanese Patent Application No. 2023-207646, filed with the Japan Patent Office on December 8, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A heat exchanger comprising a first member and a second member joined by laser welding, wherein a fluid flow path is formed between the first member and the second member, wherein the second member has a rib that is joined to the first member by the laser welding and divides the flow path, wherein a rib weld bead joining the rib to the first member has an arc portion formed in an arc at an end, and the joining depth becomes shallower toward the tip of the arc portion which is the start point or end point of the laser welding, and a leading bead and a trailing bead do not overlap in the trajectory of the rib weld bead, or the joining depth at the tip of the arc portion is a depth at which the first member and the second member are not joined.

2. A heat exchanger as claimed in claim 1, wherein the arc portion forms at least a semicircle, and the joining depth does not become shallower beyond the semicircle toward the tip end until a position where a tangent to the arc portion becomes parallel to the longitudinal direction of the rib.

3. A heat exchanger as claimed in claim 1, wherein the rib weld bead has a straight portion formed in a straight line, the straight portion extending along the longitudinal direction of the rib and formed at the centre of the rib in the width direction.

4. A heat exchanger according to claim 3, wherein a connecting portion connecting said straight portion and said arc portion is arc-shaped.

5. A heat exchanger as described in claim 1, wherein the rib has a flat portion that abuts against the first member and a wall portion rising from the flat portion, and the arc portion of the rib weld bead is formed along the R end of a curved portion that connects the flat portion and the wall portion of the rib.

6. A heat exchanger according to any one of claims 1 to 5, comprising an attachment portion for attachment to an external device, and an end of an outer periphery weld bead joining the outer periphery is located at said attachment portion.

7. A heat exchanger according to claim 6, wherein the mounting portion is a protrusion extending outwardly from the heat exchanger.

8. A method for manufacturing a heat exchanger comprising a first member and a second member joined by laser welding, wherein a fluid flow path is formed between the first member and the second member, wherein the second member has a rib that is joined to the first member by the laser welding and divides the flow path, and in the laser welding that forms a rib weld bead that joins the rib to the first member, an arc-shaped portion is formed at an end of the rib weld bead, and the joining depth becomes shallower toward the tip of the arc portion which is the start point or end point of the laser welding, and a leading bead and a trailing bead do not overlap in the trajectory of the rib weld bead, or the joining depth at the tip of the arc portion is set to a depth at which the first member and the second member are not joined.

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