Cooling device and method for manufacturing cooling device

Abstract

This cooling device comprises: a plurality of heat sinks 30 each having a flat plate-like part 31 and a fin 32 protruding from the flat plate-like part 31; a plate-like first member 10 in which a plurality of first through holes 110 for passing the fins 32 of the plurality of heat sinks 30 are formed, and to which the flat plate-like part 31 is joined; and a second member 20 which is joined to the first member 10 by being subjected to laser welding in a state of being overlapped with the first member 10, the second member 20 having a plurality of fin recesses 210 recessed from the surface overlapping with the first member 10 to accommodate the fins 32 of the plurality of heat sinks 30. In the first member 10, a first cutout 141 for dividing the plurality of first through holes 110 is formed between the plurality of first through holes 110. In the second member 20, a second cutout 242 for dividing the plurality of fin recesses 210 is formed between the plurality of fin recesses 210 at the same position as the first cutout 141.

Description

Cooling device, method for manufacturing a cooling device

[0001] The present invention relates to a cooling device and a method for manufacturing a cooling device.

[0002] For example, Patent Document 1 describes a conduction cooling structure in which a heat-generating component mounted on a substrate is conduction-cooled by a liquid refrigerant. This conduction cooling structure includes the heat-generating component composed of a package having a chip and a lid for sealing the chip, a pipe having a diameter larger than the thickness of the chip and interposed between the package and the lid, and through which a liquid refrigerant flows inside, and a tube connected to the pipe and circulating the liquid refrigerant.

[0003] Japanese Patent Application Laid-Open No. 5-121609

[0004] As a cooling device for cooling a heat-generating member, a device manufactured by laser-welding two plate-like members and having a flow path through which a liquid passes in a recess formed in at least one member can be considered. When manufacturing this cooling device, if it is necessary to irradiate laser light along the shape of the flow path, the thermal distortion increases as the length of the flow path increases. When the heat-generating members to be cooled are, for example, a plurality of ICs (Integrated Circuits) or SoCs (System on Chips) mounted on the same substrate, if the thermal distortion of the cooling device is large, the contact area with the plurality of ICs or SoCs may decrease and the cooling efficiency may decrease. An object of the present invention is to provide a cooling device and the like that can suppress thermal distortion.

[0005] The present invention, completed with this objective in mind, is a cooling device comprising: a plurality of heat sinks having a flat plate-like portion and fins protruding from the flat plate-like portion; a plate-shaped first member to which the flat plate-like portion is joined and which has a plurality of through holes formed therein through which each of the fins of the plurality of heat sinks passes; and a second member which is joined to the first member by laser welding while superimposed on the first member, and which is recessed from the overlapping surface with the first member and has a plurality of recesses that accommodate the fins of each of the plurality of heat sinks, wherein the first member has a first notch formed between the plurality of through holes that divides the plurality of through holes, and the second member has a second notch formed between the plurality of recesses at the same position as the first notch that divides the plurality of recesses. Here, the plurality of recesses are two recesses, the second member has a connecting passage recessed from the overlapping surface with the first member so as to allow the two recesses to pass through each other, and the second notch may be formed from the end of the second member to near the connecting passage. Furthermore, the second member may have a recessed connecting passage formed in the overlapping surface with the first member so as to connect a liquid inlet or outlet to one of the two recesses, the connecting passage passing through the other of the two recesses, the communication passage, and the first recess on the opposite side of the second notch to reach the first recess, the second member may have a third notch formed in the second member that separates the other recess, the communication passage, and the first recess from the connecting passage, and the first member may have a fourth notch formed in the same position as the third notch. Furthermore, the second member may have a recessed communication passage formed in the overlapping surface with the first member so as to allow two of the plurality of recesses to pass through each other, and the second notch may be formed between the recess and the communication passage.From another perspective, the present invention is a method for manufacturing a cooling device, comprising: a step of forming a plurality of heat sinks having a flat plate portion and fins protruding from the flat plate portion; a first step of forming a plate-shaped first member having a plurality of through holes through which each of the fins of the plurality of heat sinks passes; a second step of forming a second member recessed from the overlapping surface with the first member and having a plurality of recesses for accommodating the fins of each of the plurality of heat sinks, wherein the first step comprises forming a first notch between the plurality of through holes in the first member to divide the plurality of through holes; the second step comprises forming a second notch between the plurality of recesses in the second member to divide the plurality of recesses; a step of overlapping the first member and the second member so that the first notch and the second notch are in the same position; and a step of joining the first member and the second member by laser welding. Herein, prior to the overlapping step, the process may further include a step in which the flat plate portion and the first member are joined by laser welding while the flat plate portion and the first member are overlapped by passing the fins of the heat sink through the through hole of the first member formed in the first step.

[0006] According to the present invention, it is possible to provide a cooling device and the like that can suppress thermal distortion.

[0007] This figure shows an example of the external appearance of the cooling device according to the first embodiment. This figure shows an example of the external appearance of the cooling device according to the first embodiment. This is an example of a perspective view of the first member, the second member and the heat sink. This figure shows an example of a cross-section of section IV-IV in Figure 1. This is an example of a view of the cooling device from the second member side in the stacking direction. This figure shows an example of the external appearance of the cooling device according to the second embodiment. This figure shows an example of a cross-section of section VII-VII in Figure 6. This is an example of a view of the cooling device according to the second embodiment from the second member side in the stacking direction.

[0008] The embodiments will be described in detail below with reference to the attached drawings. <First Embodiment> Figures 1 and 2 show an example of the external appearance of the cooling device 1 according to the first embodiment. Figure 1 is a perspective view seen from the side of the second member 20, which will be described later, and Figure 2 is a perspective view seen from the side of the first member 10, which will be described later. Figure 3 is an example of a perspective view of the first member 10, the second member 20 and the heat sink 30. Figure 4 shows an example of a cross-section of the IV-IV section of Figure 1. Figure 5 is an example of a view of the cooling device 1 seen from the side of the second member 20 in the stacking direction.

[0009] The cooling device 1 according to the first embodiment comprises a plate-shaped first member 10, a plate-shaped second member 20 arranged opposite to the first member 10, and a plurality (two in the first embodiment) of heat sinks 30. The cooling device 1 also comprises an intake joint 40 for drawing coolant into a flow path formed between the first member 10 and the second member 20, and an exhaust joint 50 for discharging coolant from the flow path formed between the first member 10 and the second member 20.

[0010] In the following, the direction in which the first member 10 and the second member 20 are stacked may be referred to as the "stacking direction." Also, the direction in which the multiple heat sinks 30 are arranged, which is parallel to the plate surfaces of the first member 10 and the second member 20, may be referred to as the "first direction," and the direction that intersects the first direction (for example, a perpendicular direction), which is parallel to the plate surfaces of the first member 10 and the second member 20, may be referred to as the "second direction." The intake joint 40 and the discharge joint 50 are provided on one side of the second direction. In the following, in the second direction, the side on which the intake joint 40 and the discharge joint 50 are provided may be referred to as the "third side," and the other side may be referred to as the "fourth side."

[0011] (Heat sink 30) The heat sink 30 has a flat plate-shaped portion 31 and a plurality of fins 32 that protrude from the flat plate-shaped portion 31 in a direction perpendicular to the plate surface. The flat plate-shaped portion 31 has a rectangular shape when viewed in the stacking direction. The flat plate-shaped portion 31 has a first surface 311, which is the side on which the fins 32 are formed, and a flat second surface 312, which is the side on which the fins 32 are not formed. The plurality of fins 32 are formed in a part of the area near the center of the first surface 311 (in Figure 3, the area has a rectangular shape when viewed in the stacking direction), and the area outside the region on the first surface 311 on which the fins 32 are formed is a flat surface.

[0012] The fin 32 can be exemplified as a columnar shape whose protrusion direction from the flat plate portion 31 is the stacking direction. The shape obtained by cutting the fin 32 with a plane perpendicular to the protrusion direction (hereinafter sometimes referred to as the "cross-sectional shape") can be exemplified as a quadrilateral such as a square, rectangle, or rhombus. The cross-sectional shape can also be exemplified as a circle or an ellipse. The fin 32 may also be flat. If it is flat, it may be parallel to the second direction, or it may be wavy with a portion inclined in the second direction. The heat sink 30 can be exemplified as being formed by forging or cutting. The heat sink 30 is formed from at least one of copper or aluminum material.

[0013] (First Member 10) The first member 10 has multiple first through-holes 110 (the same number as the number of heat sinks 30 (two in the first embodiment)) through which each of the fins 32 of the multiple heat sinks 30 passes. The first through-holes 110 are rectangular in shape. The flat plate portion 31 of the heat sink 30 is joined to the peripheral portion 115 of the first member 10, which is the part around the first through-holes 110. The first member 10 also has multiple second through-holes 120 (four in the first embodiment) formed around the peripheral portion 115, which are through-holes for passing fixing members (e.g., bolts) (not shown) used to fix the cooling device 1 to another object. The second through-holes 120 are formed on the outside of the peripheral portion 115, at positions corresponding to each of the four corners of the first through-holes 110.

[0014] The first member 10 has two sets 130, each set having a first through-hole 110, a peripheral portion 115 around the first through-hole 110, and four second through-holes 120 formed around the peripheral portion 115, the same number as the number of heat sinks 30. In the first embodiment, these sets 130 are formed side by side in the first direction, and consist of a first set 131 provided on one side in the first direction and a second set 132 provided on the other side. Hereinafter, in the first direction, the side where the first set 131 is provided may be referred to as the "first side," and the side where the second set 132 is provided may be referred to as the "second side." Also, in the second direction, the side where the intake joint 40 and the discharge joint 50 are provided (the front side in Figure 1) may be referred to as the "third side," and the other side (the back side in Figure 1) may be referred to as the "fourth side." Furthermore, the first member 10 has a first notch 141 formed between the two sets 130, which is a notch that divides the two sets 130.

[0015] (Second Member 20) The second member 20 has multiple fin recesses 210 (the same number as the number of heat sinks 30 (two in the first embodiment)) which are recessed from the overlapping surface 21 with the first member 10 and accommodate the fins 32 of the heat sink 30. The fin recesses 210 have a rectangular shape when viewed in the stacking direction. The multiple fin recesses 210 are formed at positions corresponding to each of the multiple first through holes 110, and have a first fin recess 211 formed on the first side and a second fin recess 212 formed on the second side.

[0016] Furthermore, the second member 20 has multiple second through-holes 220 formed around the fin recess 210, at positions corresponding to each of the second through-holes 120 (for example, the same number as the second through-holes 120). In other words, the second through-holes 220 are formed on the outside of the fin recess 210, at positions corresponding to each of the four corners of the fin recess 210.

[0017] The second member 20 has two sets 230, each having a fin recess 210 and four second through holes 220 formed around the fin recess 210, the same number as the number of heat sinks 30. In the first embodiment, these sets 230 are formed side by side in the first direction and consist of a first set 231 provided on the first side and a second set 232 provided on the second side.

[0018] Furthermore, the second member 20 has an intake recess 250 formed in the overlapping surface 21 at a position corresponding to the intake joint 40. The intake recess 250 has a rectangular shape when viewed in the stacking direction, and a hole is formed at the bottom into which the intake joint 40 is fitted. The intake recess 250 functions as an inlet for flowing coolant into the first flow channel recess 271, which will be described later. Furthermore, the second member 20 has a discharge recess 260 formed in the overlapping surface 21 at a position corresponding to the discharge joint 50. The discharge recess 260 has a rectangular shape when viewed in the stacking direction, and a hole is formed at the bottom into which the discharge joint 50 is fitted. The discharge recess 260 functions as an outlet for flowing coolant out from the third flow channel recess 273, which will be described later.

[0019] Furthermore, the second member 20 has a flow path recess 270 formed in the overlapping surface 21, which serves as a flow path for the coolant. The flow path recess 270 has a first flow path recess 271 formed between the intake recess 250 and the second fin recess 212, and a second flow path recess 272 formed between the second fin recess 212 and the first fin recess 211. The flow path recess 270 also has a third flow path recess 273 formed between the first fin recess 211 and the discharge recess 260.

[0020] The first flow channel recess 271 is formed so that coolant flows into the second fin recess 212 from the third side in the second direction. The second flow channel recess 272 is formed so that coolant flows out from the second fin recess 212 to the fourth side in the second direction, and coolant flows into the first fin recess 211 from the fourth side in the second direction. Furthermore, the second flow channel recess 272 is formed so that the coolant passes outside the second through hole 120.

[0021] The third flow channel recess 273 is formed so that coolant flows out from within the first fin recess 211 to the third side in the second direction, and coolant flows into the discharge recess 260 from the fourth side in the second direction. Furthermore, the third flow channel recess 273 is formed so that the coolant passes outside the first set 231 and the second set 232, passing through the first side in the first direction of the first set 231, the fourth side in the second direction of the first set 231 and the second set 232, and the second side in the first direction of the second set 232 to reach the discharge recess 260.Hereinafter, the portion of the third flow channel recess 273 formed on the first side of the first set 231 may be referred to as the "first side third recess 281". Also, the portion of the third flow channel recess 273 formed on the fourth side in the second direction of the first set 231 and the second set 232 may be referred to as the "fourth side third recess 284". Furthermore, the portion of the third flow channel recess 273 formed on the second side of the second set 232 may be referred to as the "second side third recess 282".

[0022] Furthermore, the second member 20 has a second notch 242 formed between the multiple sets 230, which is a notch that divides the multiple sets 230. In the example shown in Figure 3, the second notch 242 is formed between the first set 231 and the second set 232, which are two sets 230, and divides the first set 231 and the second set 232. The second notch 242 is formed from the third end of the second member 20 to near the second flow channel recess 272 (the part third to the second flow channel recess 272). Also, the second notch 242 is formed at a position corresponding to the first notch 141 formed in the first member 10. In other words, the first notch 141 is formed from the third end of the first member 10 to near the second flow channel recess 272 (the part third to the second flow channel recess 272).

[0023] Furthermore, the second member 20 has a third notch 243 formed therein, which is a cutout that separates the fourth side third recess 284 from the plurality of sets 230 and the second flow channel recess 272. The third notch 243 is formed between the first side third recess 281 and the second side third recess 282 so as to extend in the first direction. Also, the third notch 243 is formed at a position corresponding to the fourth notch 144 formed in the first member 10. In other words, the fourth notch 144 is formed between the first side third recess 281 and the second side third recess 282 so as to extend in the first direction.

[0024] The intake joint 40 and the discharge joint 50 are cylindrical members. The material and manufacturing method of the intake joint 40 and the discharge joint 50 are not particularly limited. For example, the intake joint 40 and the discharge joint 50 can be formed into a cylindrical shape by rolling up a rectangular thin sheet of aluminum and then joining the ends together.

[0025] In the cooling device 1, the fins 32 of the heat sink 30 are housed in the fin recesses 210 of the second member 20, and the flat plate portion 31 is exposed to the outside, with the first member 10 and the second member 20 joined by laser welding. In the cooling device 1, for example, multiple ICs (not shown) and SoCs (not shown) mounted on a single substrate (not shown) are each provided on the second surface 312 of the flat plate portion 31 of the heat sink 30. The flow path recesses 270 formed in the second member 20 function as flow paths for the coolant that flows in from the intake joint 40 and flows out from the discharge joint 50, and the heat generated by the multiple ICs and SoCs is dissipated by the coolant and the heat sink 30.

[0026] (Manufacturing Method) Next, the manufacturing method of the cooling device 1 will be described. The manufacturing method of the cooling device 1 comprises the steps of molding a plurality of heat sinks 30, the first step of molding the first member 10, and the second step of molding the second member 20. The manufacturing method of the cooling device 1 also comprises the steps of joining the heat sinks 30 and the first member 10, overlapping the first member 10 and the second member 20, and joining the first member 10 and the second member 20. The manufacturing method of the cooling device 1 also comprises the steps of joining the intake joint 40 to the second member 20 and joining the discharge joint 50 to the second member 20.

[0027] The first step includes forming a plurality of first through holes 110 through which each of the fins 32 of the plurality of heat sinks 30 passes, and forming a first notch 141 between the plurality of first through holes 110 that divides the plurality of first through holes 110. The second step includes forming a plurality of fin recesses 210 that are recessed from the overlapping surface 21 with the first member 10 and accommodate the fins 32 of each of the plurality of heat sinks 30. The second step also includes forming a second notch 242 between the plurality of fin recesses 210 that divides the plurality of fin recesses 210.

[0028] The step of joining the heat sink 30 and the first member 10 includes a step of joining the flat plate portion 31 and the first member 10 by laser welding, with the fins 32 of the heat sink 30 passing through the first through-hole 110 of the first member 10 and the flat plate portion 31 overlapping. When joining, the first member 10 is placed on the first surface 311 of the flat plate portion 31 and laser light is irradiated toward the first member 10 at the overlapping portion between the flat plate portion 31 and the first member 10. Then, the laser head (not shown) is moved around the area where the fins 32 are formed and the laser light is irradiated continuously. As a result, the joint W0 between the heat sink 30 and the first member 10 becomes the overlapping portion between the flat plate portion 31 and the first member 10 around the fins 32. Note that the method of joining the heat sink 30 and the first member 10 may also be brazing.

[0029] The process of joining the first member 10 and the second member 20 includes a step of joining by laser welding. The joint W1 between the first member 10 and the second member 20 is around the multiple fin recesses 210, suction recesses 250, discharge recesses 260 and flow path recesses 270, and is the area shown by the thick line in Figure 5. When joining the first member 10 and the second member 20, laser light is irradiated toward the second member 20 at the overlapping portion of the first member 10 and the second member 20, and the laser head (not shown) is moved along the thick line shown in Figure 5 to continuously irradiate with laser light. By making the joint W1 (in other words, the area irradiated with laser light) the area shown by the thick line in Figure 5, the first member 10 and the second member 20 can be joined by continuously moving the laser head without stopping the irradiation of the laser light.

[0030] The step of joining the intake joint 40 to the second member 20 includes inserting one end of the intake joint 40 into the intake recess 250 of the second member 20 through a hole formed in the intake recess 250, while the other end is exposed to the outside, and then performing laser welding. The step of joining the discharge joint 50 to the second member 20 includes inserting one end of the discharge joint 50 into the discharge recess 260 of the second member 20 through a hole formed in the discharge recess 260, while the other end is exposed to the outside, and then performing laser welding. Note that the method of joining the intake joint 40 and the discharge joint 50 to the second member 20 is not limited to laser welding; other welding methods or methods other than welding, such as adhesive bonding, may also be used. Furthermore, the intake joint 40 and the discharge joint 50 to the second member 20 may be joined after joining the first member 10 and the second member 20, or before joining the first member 10 and the second member 20. If the suction joint 40 and discharge joint 50 are joined to the second member 20 before joining the first member 10 and the second member 20, laser light may be irradiated from the overlapping surface 21 side of the second member 20.

[0031] As described above, the cooling device 1 comprises a plurality of heat sinks 30 and a plate-shaped first member 10 to which a flat plate portion 31 is joined, and which has a plurality of first through holes 110 (an example of through holes) through which each of the fins 32 of the plurality of heat sinks 30 passes. The cooling device 1 also comprises a second member 20 which is joined to the first member 10 by laser welding while superimposed on the first member 10, and which is recessed from the overlapping surface 21 with the first member 10 and has a plurality of fin recesses 210 (an example of recesses) that accommodate the fins 32 of each of the plurality of heat sinks 30. The first member 10 has a first notch 141 formed between the plurality of first through holes 110 that divides the plurality of first through holes 110. The second member 20 has a second notch 242 formed between the plurality of fin recesses 210 at the same position as the first notch 141 that divides the plurality of fin recesses 210.

[0032] According to the cooling device 1 described above, for example, the heat generated when welding the first member 10 and the second member 20 around one of the multiple first through holes 110 and fin recesses 210 is less likely to be transmitted to the other first through holes 110 and fin recesses 210. In other words, a first notch 141 and a second notch 242 are formed that separate the area where one of the multiple heat sinks 30 is located from the area where the other heat sinks 30 are located. Therefore, the heat generated when welding the area where one heat sink 30 is located can be suppressed from affecting the shape of the area where the other heat sinks 30 are located, thereby suppressing thermal distortion in the area where the other heat sinks 30 are located.

[0033] Furthermore, in the cooling device 1, the plurality of fin recesses 210 are two recesses, a first fin recess 211 and a second fin recess 212. The second member 20 has a second flow channel recess 272 (an example of a connecting passage) formed in the overlapping surface 21 with the first member 10 so as to allow the two recesses to pass through each other. The second notch 242 is formed from the end of the second member 20 to near the second flow channel recess 272. As a result, for example, heat generated when welding the area where one heat sink 30 is placed can be reliably and effectively prevented from being transferred to the area where another heat sink 30 is placed, and thermal distortion in the area where the other heat sink 30 is placed can be reliably suppressed.

[0034] Furthermore, the second member 20 has a third flow channel recess 273 (an example of a connecting passage) recessed from the overlapping surface 21 with the first member 10 so as to connect the discharge recess 260 (an example of a liquid outlet) and the first fin recess 211 (an example of a single recess). The third flow channel recess 273 passes on the opposite side of the second notch 242 from the second fin recess 212 (an example of another recess), the second flow channel recess 272 and the first fin recess 211, and reaches the first fin recess 211. The second member 20 has a third notch 243 that separates the second fin recess 212, the second flow channel recess 272 and the first fin recess 211 from the third flow channel recess 273, and the first member 10 has a fourth notch 144 formed at the same position as the third notch 243. This makes it difficult for the heat generated when welding around the third flow channel recess 273 to be transferred to the area where the two heat sinks 30 are located, thereby suppressing thermal distortion in the area where the two heat sinks 30 are located.

[0035] In the method for manufacturing the cooling device 1, the step of joining the heat sink 30 and the first member 10 described above may be performed before or after the step of joining the first member 10 and the second member 20. Alternatively, the joining of the heat sink 30 and the first member 10, and the joining of the first member 10 and the second member 20 may be performed simultaneously with the first member 10 superimposed on the flat plate portion 31 of the heat sink 30 and the second member 20 superimposed on the first member 10. For example, the heat sink 30, the first member 10, and the second member 20 may be joined by irradiating the second member 20 at the overlapping portion of the flat plate portion 31 of the heat sink 30 and the first member 10.

[0036] <Second Embodiment> Figure 6 is a diagram showing an example of the external appearance of the cooling device 2 according to the second embodiment. Figure 7 is a diagram showing an example of a cross-section of section VII-VII in Figure 6. Figure 8 is an example of a view of the cooling device 2 according to the second embodiment from the second member 70 side in the stacking direction. The cooling device 2 according to the second embodiment differs from the cooling device 1 according to the first embodiment in that it has three heat sinks 30 arranged in the first direction. The differences from the first embodiment will be described below. The same reference numerals are used for the same components in the first and second embodiments, and their detailed descriptions will be omitted.

[0037] More specifically, the cooling device 2 includes a first member 60 and a second member 70 corresponding to the first member 10 and the second member 20 in the first embodiment, and three heat sinks 30 arranged in a first direction.

[0038] (First Member 60) The first member 60 has sets 630 corresponding to sets 130, each having a first through hole 110, a surrounding portion 115, and four second through holes 120, at positions corresponding to each of the three heat sinks 30. The three sets 630 consist of a first set 631 located on the first side, a second set 632 located on the second side, and an intermediate set 633 located between the first set 631 and the second set 632. The first member 60 has first notches 641 that divide the space between the first set 631 and the intermediate set 633, and between the second set 632 and the intermediate set 633.

[0039] (Second Member 70) The second member 70 has sets 730 corresponding to sets 230 having fin recesses 210 and four second through holes 220 at positions corresponding to each of the three heat sinks 30. The three sets 730 include a first set 731 located on the first side, a second set 732 located on the second side, and an intermediate set 733 located between the first set 731 and the second set 732. The second member 70 has a second notch 742 which is a cutout that separates the first set 731 from the intermediate set 733, and the second set 732 from the intermediate set 733.

[0040] The second member 70 has a flow channel recess 770 formed in the overlapping surface 71 with the first member 60, which serves as a flow channel for the coolant. The flow channel recess 770 includes a first flow channel recess 771 formed between the inlet 750 and the fin recess 210 of the first set 731, and a second flow channel recess 772 formed between the fin recess 210 of the first set 731 and the fin recess 210 of the intermediate set 733. The flow channel recess 770 also includes a third flow channel recess 773 formed between the fin recess 210 of the intermediate set 733 and the fin recess 210 of the second set 732, and a fourth flow channel recess 774 formed between the fin recess 210 of the second set 732 and the discharge section 760.

[0041] The first flow channel recess 771 is formed so that coolant flows into the fin recess 210 of the first set 731 from the third side in the second direction. The second flow channel recess 772 is formed so that coolant flows out from the fin recess 210 of the first set 731 to the third side in the second direction, and coolant flows into the fin recess 210 of the intermediate set 733 from the fourth side in the second direction. Furthermore, the second flow channel recess 772 is formed so that the coolant passes outside the second through hole 220 of the first set 731.

[0042] The third flow path recess 773 is formed such that the coolant flows out from within the fin recess 210 of the intermediate set 733 toward the fourth side in the second direction and the coolant flows into the fin recess 210 of the second set 732 from the third side in the second direction. Further, the third flow path recess 773 is formed such that the coolant passes outside the second through hole 220 of the second set 732. The fourth flow path recess 774 is formed such that the coolant flows out from within the fin recess 210 of the second set 732 toward the third side in the second direction.

[0043] The second notch 742 is formed between the fin recess 210 and the second through hole 220 that constitute the set 730 and the flow path recess 770. However, the second notch 742 is not formed outside one side of the rectangular shape in the fin recess 210 of each set 730, that is, the side where the flow path recess 770 for the inflow and outflow of the coolant is formed with respect to the fin recess 210. That is, the second notch 742 is not formed on the third side of the first set 731 and the second set 732 and the fourth side of the intermediate set 733. Thereby, the inflow of the coolant into each fin recess 210 and the outflow of the coolant from each fin recess 210 are enabled.

[0044] The first member 60 and the second member 70 configured as described above are joined by laser welding. The joining portion W2 joined by performing laser welding is around a plurality of fin recesses 210 and flow path recesses 770, and is the portion indicated by the thick line in FIG. 8. More specifically, the joining portion W2 has a first joining portion W3 provided outside a plurality of fin recesses 210 and flow path recesses 770, indicated by a solid line in FIG. 8, and a second joining portion W4 provided inside a plurality of fin recesses 210 and flow path recesses 770, indicated by a broken line in FIG. 8.

[0045] In the cooling device 2 configured as described above, the coolant flows into the flow path recess 770 from the opening in the first flow path recess 771, and the inflowed coolant passes through the flow path recess 770 and the fins 32 of the three heat sinks 30 and flows out from the opening in the fourth flow path recess 774.

[0046] As described above, the cooling device 2 comprises a heat sink 30 and a plate-shaped first member 60 through which a plurality of first through holes 110 (an example of through holes) are formed, through which each of the fins 32 of the plurality of heat sinks 30 passes, and to which a flat plate-shaped portion 31 is joined. The cooling device 2 also comprises a second member 70 which is joined to the first member 60 by laser welding while superimposed on the first member 60, and which is recessed from the overlapping surface 71 with the first member 60 and has a plurality of fin recesses 210 (an example of recesses) that accommodate the fins 32 of each of the plurality of heat sinks 30. The first member 60 has a first notch 641 formed between the plurality of first through holes 110 that divides the plurality of first through holes 110. The second member 70 has a second notch 742 formed between the plurality of fin recesses 210 at the same position as the first notch 641 that divides the plurality of fin recesses 210.

[0047] In the cooling device 2 described above, a first notch 641 and a second notch 742 are formed that separate the area where one of the multiple heat sinks 30 is located from the area where the other heat sinks 30 are located. Therefore, the heat generated when welding the area where one heat sink 30 is located can be suppressed from affecting the shape of the area where the other heat sinks 30 are located, thereby suppressing thermal distortion in the area where the other heat sinks 30 are located. Furthermore, the heat generated when welding the area where the other heat sinks 30 are located can be suppressed from affecting the shape of the area where one heat sink 30 is located, thereby suppressing thermal distortion in the area where one heat sink 30 is located.

[0048] Further, in the second member 70, a second flow path recess 772 (an example of a communication path), which is recessed from the overlapping surface 71 with the first member 60 so as to pass through between two fin recesses 210 (for example, the fin recess 210 of the first set 731 and the fin recess 210 of the intermediate set 733), is formed. And the second notch 742 is formed between the fin recess 210 of the first set 731 and the second flow path recess 772. Thereby, heat during welding around the second flow path recess 772 can be made difficult to be transmitted to the fin recess 210 of the first set 731, and thermal distortion of the fin recess 210 of the first set 731 where the heat sink 30 is disposed can be suppressed.

[0049] Further, in the second member 70, a third flow path recess 773 (an example of a communication path), which is recessed from the overlapping surface 71 with the first member 60 so as to pass through between two fin recesses 210 (for example, the fin recess 210 of the second set 732 and the fin recess 210 of the intermediate set 733), is formed. And the second notch 742 is formed between the fin recess 210 of the second set 732 and the third flow path recess 773. Thereby, heat during welding around the third flow path recess 773 can be made difficult to be transmitted to the fin recess 210 of the second set 732, and thermal distortion of the fin recess 210 of the first set 731 where the heat sink 30 is disposed can be suppressed.

[0050] 1, 2... cooling device, 10, 60... first member, 20, 70... second member, 30... heat sink, 31... flat plate portion, 32... fin, 110... first through hole (an example of a through hole), 141, 641... first notch, 210... fin recess (an example of a recess), 242, 742... second notch, 250... suction recess (an example of an inflow portion), 260... discharge recess (an example of an outflow portion), 272, 772... second flow path recess (an example of a communication path), 273... third flow path recess (an example of a connection path)

Claims

1. A cooling device comprising: a plurality of heat sinks having a flat plate-like portion and fins protruding from the flat plate-like portion; a plate-shaped first member to which the flat plate-like portions are joined and which has a plurality of through holes formed therein through which each of the fins of the plurality of heat sinks passes; and a second member which is joined to the first member by laser welding while superimposed on the first member, and which is recessed from the overlapping surface with the first member and has a plurality of recesses for accommodating the fins of each of the plurality of heat sinks, wherein the first member has a first notch formed between the plurality of through holes that divides the plurality of through holes, and the second member has a second notch formed between the plurality of recesses at the same position as the first notch that divides the plurality of recesses.

2. The cooling device according to claim 1, wherein the plurality of recesses are two recesses, the second member has a recessed passage formed from the overlapping surface with the first member so as to allow the two recesses to pass through each other, and the second notch is formed from the end of the second member to near the passage.

3. The cooling device according to claim 2, wherein the second member has a recessed connecting passage formed in the overlapping surface with the first member so as to connect a liquid inlet or outlet to one of the two recesses, the connecting passage reaches the first recess by passing on the opposite side of the second notch to the other recess of the two recesses, the communication passage and the first recess, the second member has a third notch formed therein that separates the other recess, the communication passage and the first recess from the connecting passage, and the first member has a fourth notch formed in the same position as the third notch.

4. The cooling device according to claim 1, wherein the second member has a recessed passage formed in the overlapping surface with the first member so as to allow two of the plurality of recesses to pass through each other, and the second notch is formed between the recess and the passage.

5. A method for manufacturing a cooling device, comprising: a step of forming a plurality of heat sinks having a flat plate portion and fins protruding from the flat plate portion; a first step of forming a plate-shaped first member having a plurality of through holes through which each of the fins of the plurality of heat sinks passes; a second step of forming a second member recessed from the overlapping surface with the first member and having a plurality of recesses for accommodating the fins of each of the plurality of heat sinks, wherein the first step includes forming a first notch between the plurality of through holes in the first member to divide the plurality of through holes; the second step includes forming a second notch between the plurality of recesses in the second member to divide the plurality of recesses; a step of overlapping the first member and the second member so that the first notch and the second notch are in the same position; and a step of joining the first member and the second member by laser welding.

6. The method for manufacturing a cooling device according to claim 5, further comprising the step of joining the flat plate portion and the first member by laser welding while the flat plate portion and the first member are overlapped by passing the fins of the heat sink through the through holes of the first member formed in the first step, prior to the overlapping step.

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