Cooling device, method for manufacturing a cooling device

Abstract

To provide a cooling device, etc., that can suppress thermal distortion. [Solution] The invention comprises a plurality of heat sinks 30 having a flat plate portion 31 and fins 32 protruding from the flat plate portion 31; a plate-shaped first member 10 to which the flat plate portion 31 is joined and which has a plurality of first through holes 110 through which each of the fins 32 of the plurality of heat sinks 30 passes; and 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 with the first member 10 and has a plurality of fin recesses 210 that accommodate the fins 32 of each of the plurality of heat sinks 30. The first member 10 has a first notch 141 between the plurality of first through holes 110 that divides the plurality of first through holes 110, and the second member 20 has a second notch 242 between the plurality of fin recesses 210 at the same position as the first notch 141 that divides the plurality of fin recesses 210.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 describes a conduction cooling structure that conducts heat from a heat-generating component mounted on a substrate using 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 with a liquid refrigerant flowing inside, and a tube connected to the pipe for circulating the liquid refrigerant.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[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 becomes larger 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 become small 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.

Means for Solving the Problems

[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 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. Here, the plurality of recesses are two recesses, and 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 may be formed from the end of the second member to near the passage. Furthermore, 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 from the other of the two recesses, the communication passage and the first recess, and the second member has a third notch 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 passage formed in the overlapping surface with the first member, allowing two of the plurality of recesses to pass through each other, and the second notch may be formed between the recess and the 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 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 hole of the first member formed in the first step. [Effects of the Invention]

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

[0007] [Figure 1] This figure shows an example of the appearance of a cooling device according to the first embodiment. [Figure 2] This figure shows an example of the appearance of a cooling device according to the first embodiment. [Figure 3] This is an example of a perspective view of the first component, the second component, and the heat sink. [Figure 4] This figure shows an example of a cross-section of section IV-IV in Figure 1. [Figure 5] This is an example of a diagram showing a cooling device viewed from the second member side in the stacking direction. [Figure 6] This figure shows an example of the appearance of a cooling device according to the second embodiment. [Figure 7] This figure shows an example of a cross-section of section VII-VII in Figure 6. [Figure 8] This is an example of a cooling device according to the second embodiment, viewed from the second member side in the stacking direction. [Modes for carrying out the invention]

[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 from the side of the second member 20, which will be described later, and Figure 2 is a perspective view 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 section IV-IV in Figure 1. Figure 5 is an example of a view of the cooling device 1 from the second member 20 side 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." Furthermore, 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 portion 31 has a rectangular shape when viewed in the stacking direction. The flat plate portion 31 has a first surface 311 on which the fins 32 are formed, and a second surface 312 on which the fins 32 are not formed and is flat. Multiple fins 32 are formed in a part of the first surface 311 near the center (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 where 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. Alternatively, the cross-sectional shape can be a circle or an ellipse. Furthermore, the fin 32 may 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 by being formed by forging or machining. Furthermore, the heat sink 30 is formed from at least one of copper or aluminum.

[0013] (First member 10) The first member 10 has a plurality of first through-holes 110 (the same number as the number of heat sinks 30, which is two in the first embodiment) that are through-holes through which the fins 32 of the plurality of heat sinks 30 are respectively passed. The first through-holes 110 are rectangular. The flat plate portion 31 of the heat sink 30 is joined to the peripheral portion 115, which is a portion around the first through-holes 110 in the first member 10. Further, the first member 10 has a plurality of second through-holes 120 (four in the first embodiment), which are through-holes through which fixing members (e.g., bolts) (not shown) used to fix the cooling device 1 to other objects are passed, around the peripheral portion 115. The second through-holes 120 are formed outside the peripheral portion 115 and at positions corresponding to the four corners of the first through-holes 110 respectively.

[0014] The first member 10 has a plurality of sets 130 (the same number as the number of heat sinks 30, i.e., two in the first embodiment), each set having the first through-holes 110, the peripheral portion 115 around the first through-holes 110, and the four second through-holes 120 formed around the peripheral portion 115. The two sets 130 are formed to be arranged in the first direction and include 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 suction joint 40 and the discharge joint 50 are provided (the front side in FIG. 1) may be referred to as the "third side", and the other side (the back side in FIG. 1) may be referred to as the "fourth side". Further, the first member 10 has a first notch 141, which is a notch that divides the two sets 130, formed between 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)) formed in the overlapping surface 21 with the first member 10, which are recessed 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 a 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 introducing 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 that discharges coolant 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 within 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 both 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 both 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 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 two sets 230, namely the first set 231 and the second set 232, which is a notch that 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 multiple 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 within 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) or 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 channel recesses 270 formed in the second member 20 function as flow channels through which the coolant flows in from the intake joint 40 and out from the discharge joint 50, dissipating the heat generated by the multiple ICs or SoCs through the coolant and the heat sink 30.

[0026] (Manufacturing method) Next, we will describe the manufacturing method of the cooling device 1. The manufacturing method for the cooling device 1 comprises the steps of forming a plurality of heat sinks 30, forming a first member 10, and forming a second member 20. The manufacturing method for 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 for 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 process of joining the heat sink 30 and the first member 10 includes the 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, intake 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 to which laser light is irradiated) 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 laser light.

[0030] The step of joining the suction joint 40 to the second member 20 includes inserting one end of the suction joint 40 into the suction recess 250 of the second member 20 through a hole formed in the suction 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. Furthermore, the method for 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. In addition, the intake joint 40 and the discharge joint 50 may be joined to the second member 20 either 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 intake joint 40 and the 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, when welding the first member 10 and the second member 20 around one of the multiple first through holes 110 and fin recesses 210, the heat is less likely to be transferred 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 multiple 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 connect the two recesses. The second notch 242 is formed from the end of the second member 20 to near the second flow channel recess 272. This makes it possible to reliably prevent heat from being transferred when welding a part where one heat sink 30 is placed to a part where another heat sink 30 is placed, and to reliably suppress thermal distortion in the part where the other heat sink 30 is placed.

[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 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 shows an example of the external appearance of the cooling device 2 according to the second embodiment. Figure 7 shows 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, as seen 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 a 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, respectively, 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 also has first notches 641, which are notches 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, each 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 consist of 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 also has second notches 742, which are notches that divide the space between the first set 731 and the intermediate set 733, and between the second set 732 and 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 within 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 channel recess 773 is formed so that coolant flows out from within the fin recess 210 of the intermediate set 733 to the fourth side in the second direction, and coolant flows into the fin recess 210 of the second set 732 from the third side in the second direction. Furthermore, the third flow channel recess 773 is formed so that the coolant passes outside the second through hole 220 of the second set 732. The fourth flow channel recess 774 is formed so that the coolant flows out from within the fin recess 210 of the second set 732 to 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 on the outside of one rectangular side of the fin recess 210 of each set 730, where the flow path recess 770 for the inflow and outflow of coolant to and from the fin recess 210 is formed. In other words, the second notch 742 is not formed on the third side of the first set 731 and the second set 732, and on the fourth side of the intermediate set 733. This allows for the inflow of coolant to each fin recess 210 and the outflow of coolant from each fin recess 210.

[0044] The first member 60 and the second member 70, configured as described above, are joined by laser welding. The joining area W2, which is joined by laser welding, is around the multiple fin recesses 210 and the flow channel recesses 770, and is shown by a thick line in Figure 8. More specifically, the joining area W2 has a first joining area W3 provided on the outside of the multiple fin recesses 210 and the flow channel recesses 770, shown by a solid line in Figure 8, and a second joining area W4 provided on the inside of the multiple fin recesses 210 and the flow channel recesses 770, shown by a dashed line in Figure 8.

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

[0046] As described above, the cooling device 2 comprises a heat sink 30 and a plate-shaped first member 60 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 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 placed from the area where the other heat sinks 30 are placed. Therefore, the heat generated when welding the area where one heat sink 30 is placed can be suppressed from affecting the shape of the area where the other heat sinks 30 are placed, thereby suppressing thermal distortion in the area where the other heat sinks 30 are placed. Furthermore, the heat generated when welding the area where the other heat sinks 30 are placed can be suppressed from affecting the shape of the area where one heat sink 30 is placed, thereby suppressing thermal distortion in the area where one heat sink 30 is placed.

[0048] Furthermore, the second member 70 has a second flow channel recess 772 (an example of a connecting passage) formed in the overlapping surface 71 with the first member 60, allowing 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) to pass through each other. The second notch 742 is formed between the fin recess 210 of the first set 731 and the second flow channel recess 772. This makes it difficult for heat generated when welding around the second flow channel recess 772 to be transferred to the fin recess 210 of the first set 731, thereby suppressing thermal distortion of the fin recess 210 of the first set 731 where the heat sink 30 is placed.

[0049] Furthermore, the second member 70 has a third flow channel recess 773 (an example of a connecting passage) recessed from the overlapping surface 71 with the first member 60 so as to allow two fin recesses 210 to pass through each other (for example, the fin recess 210 of the second set 732 and the fin recess 210 of the intermediate set 733). The second notch 742 is formed between the fin recess 210 of the second set 732 and the third flow channel recess 773. This makes it difficult for heat generated when welding around the third flow channel recess 773 to be transferred to the fin recess 210 of the second set 732, thereby suppressing thermal distortion of the fin recess 210 of the first set 731 where the heat sink 30 is placed. [Explanation of symbols]

[0050] 1,2…Cooling device, 10,60…First component, 20,70…Second component, 30…Heat sink, 31…Flat plate portion, 32…Fin, 110…First through hole (example of a through hole), 141,641…First notch, 210…Fin recess (example of a recess), 242,742…Second notch, 250…Intake recess (example of an inlet), 260…Discharge recess (example of an outlet), 272,772…Second flow path recess (example of a connecting passage), 273…Third flow path recess (example of a connecting passage)

Claims

1. A plurality of heat sinks having a flat plate-shaped portion and fins protruding from the flat plate-shaped portion, A plate-shaped first member is formed in which multiple through holes are formed through which each of the fins of the multiple heat sinks, and the flat plate portion is joined to it, A second member is joined to the first member by laser welding while superimposed on the first member, and has a recess in 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, Equipped with, The first member has a first notch formed between the plurality of through holes that divides the plurality of through holes. The second member has a second notch formed between the plurality of recesses, at the same position as the first notch, which divides the plurality of recesses. Cooling device.

2. The aforementioned plurality of recesses consist of two recesses, The second member has a recessed passage formed in the overlapping surface with the first member, allowing the two recesses to pass through each other. The second notch is formed from the end of the second member to near the communication passage. The cooling device according to claim 1.

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

4. The second member has a recessed passage formed in the overlapping surface with the first member, such that two of the plurality of recesses are connected to each other. The second notch is formed between the recess and the communication passage. The cooling device according to claim 1.

5. A process for forming a plurality of heat sinks having a flat plate portion and fins protruding from the flat plate portion, A first step is to form 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 involves forming a second member 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, Equipped with, The first step includes forming a first notch between the plurality of through holes in the first member that divides the plurality of through holes, The second step includes forming a second notch between the plurality of recesses in the second member that divides 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, A step of joining the first member and the second member by laser welding, Furthermore, A method for manufacturing a cooling device.

6. Prior to the overlapping step, the process further includes a 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 hole of the first member formed in the first step. A method for manufacturing a cooling device according to claim 5.

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