Cooling unit and method for manufacturing same, and electronic apparatus

Abstract

A cooling unit (1) comprises: a metal base part (2) which is formed in a flat plate shape and has one surface on which an electronic component (41) can be disposed; and a resin cooling part (3) which is provided on another surface of the base part (2) and uses a refrigerant to cool the electronic component (41). The cooling part (3) has: a peripheral wall part (31) configured so that the base end side thereof is joined to the base part (2) and includes an opening (310) on the top end side thereof; and a cover part (32) joined so as to close the opening (310) of the peripheral wall part (31). The cooling unit (1) has a flow path (33) that is surrounded by the base part (2) and the cooling part (3), and through which a refrigerant can flow. The flow path (33) includes a section (201) corresponding to a section (200) which is part of the other surface of the base part (2) and which is where the electronic component (41) is disposed.

Description

Cooling unit, manufacturing method thereof, and electronic device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-19060, filed on February 12, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a cooling unit, a manufacturing method thereof, and an electronic device.

[0003] BACKGROUND ART Conventionally, electronic devices have been known that include electronic components therein and a cooling unit that can cool the electronic components with a refrigerant. For example, a cooling unit used in this type of electronic device is described in Patent Document 1.

[0004] Specifically, the cooler (cooling unit) 20 in Patent Document 1 includes a case 90 made of a box-shaped member with an opening at the top, a heat sink 10 that closes the opening of the case 90, a cooling medium inlet 92, and a cooling medium outlet 94. The case 90 is made of a metal material such as aluminum. In this cooler 20, electronic components are attached to the upper surface of the heat sink 10, which is one of the outer surfaces of the cooler 20, and the lower surface of the heat sink 10 constitutes one of the inner surfaces of the cooler 20 and comes into contact with a refrigerant. Therefore, in the cooler 20, a refrigerant flows between the case 90 and the heat sink 10.

[0005] WO2019 / 176620 A1

[0006] However, the cooler 20 of Patent Document 1 is heavy because the case 90 is made of a metal material, and the degree of freedom in shape is limited, resulting in an unnecessarily large size for cooling a desired location. Furthermore, even if the case 90 were made of resin to reduce weight while keeping the shape of the cooler 20 of Patent Document 1, and an attempt was made to injection mold the case 90 onto the heat sink 10, molding would be impossible because the box-shaped case 90 would have an under-shaped configuration.

[0007] The present disclosure has been made in consideration of such problems, and aims to provide a cooling unit that can be made lightweight, has a high degree of freedom in shape, and can be molded without becoming under-shaped during injection molding, a method for manufacturing the same, and electronic equipment that uses the same.

[0008] The first disclosure is a cooling unit having a metal base portion formed in a flat plate shape and capable of arranging electronic components on one surface thereof, and a resin cooling portion provided on the other surface of the base portion for cooling the electronic components using a refrigerant, wherein the cooling portion has a peripheral wall portion whose base end is joined to the other surface of the base portion and which has an opening on its tip end, and a cover portion joined to the opening of the peripheral wall portion so as to close the opening, and the cooling unit is surrounded by the base portion and the cooling portion and allows the refrigerant to flow through it, and has a flow path including a portion of the other surface of the base portion corresponding to the portion where the electronic components are arranged.

[0009] A second disclosure is the cooling unit according to the first disclosure, further comprising a partition wall portion within the flow path for dividing the inside of the flow path.

[0010] A third disclosure is a cooling unit according to the first or second disclosure, wherein fine irregularities are formed on the other surface of the base portion at a portion where the peripheral wall portion is joined.

[0011] The fourth disclosure is a method for manufacturing a cooling unit having a metal base portion formed in a flat plate shape and capable of arranging electronic components on one surface thereof, and a resin cooling portion provided on the other surface of the base portion for cooling the electronic components using a refrigerant, the method comprising: a peripheral wall portion forming step of injection molding a peripheral wall portion having an opening on a tip side onto the other surface of the base portion and joining the base end side of the peripheral wall portion; and a cooling portion forming step of joining a cover portion pre-formed in a shape capable of closing the opening of the peripheral wall portion to the opening, thereby forming the cooling portion having the peripheral wall portion and the cover portion, wherein in the cooling portion forming step, a flow path is formed that is surrounded by the base portion and the cooling portion and allows the refrigerant to flow through, and includes a portion of the other surface of the base portion that corresponds to the portion where the electronic components are arranged.

[0012] The fifth disclosure is a method for manufacturing a cooling unit, in which, in the peripheral wall portion forming step, a surface treatment is performed to form fine irregularities on the other surface of the base portion, on the portion where the base end side of the peripheral wall portion is to be joined.

[0013] The sixth disclosure is the method for manufacturing a cooling unit according to the fifth disclosure, wherein the surface treatment is performed by laser processing.

[0014] A seventh disclosure is a method for manufacturing a cooling unit, in any one of the fourth to sixth disclosures, wherein in the cooling portion forming process, the peripheral wall portion and the cover portion are joined by vibration welding.

[0015] The eighth disclosure is a method for manufacturing a cooling unit according to the seventh disclosure, which comprises forming a protrusion by protruding at least one of a surface of the peripheral wall portion that is to be joined to the cover portion and a surface of the cover portion that is to be joined to the peripheral wall portion, and forming an inner convex portion on at least one of the peripheral wall portion and the cover portion at a position inwardly closer to the flow path than the protrusion, and forming an inner space between the protrusion and the inner convex portion by joining the protrusion by vibration welding.

[0016] A ninth disclosure is an electronic device comprising: a cooling unit according to any one of the first to third disclosures; an electronic component arranged on one surface of the base portion of the cooling unit; and a case body that houses the cooling unit, wherein the refrigerant is supplied to the flow path in the cooling unit from outside the case body, and the refrigerant that has circulated through the flow path can be discharged to the outside of the case body.

[0017] A tenth disclosure is an electronic device having: a cooling unit according to any one of the first to third disclosures; the electronic component arranged on one surface of the base portion of the cooling unit; a case body that houses the cooling unit; a supply pipe connected to the outer surface of the case body and for supplying the refrigerant to the case body; a discharge pipe connected to the outer surface of the case body and for discharging the refrigerant from the case body; a first connecting pipe provided within the case body and connecting the supply pipe to a first through hole formed in the base portion of the cooling unit and communicating with the flow path of the cooling unit; and a second connecting pipe provided within the case body and connecting the discharge pipe to the second through hole formed in the base portion of the cooling unit and communicating with the flow path of the cooling unit.

[0018] The cooling unit of the first disclosure has a resin cooling section provided on the other surface of the metal base section, thereby enabling a lighter weight than conventional cooling units with metal cooling sections. Furthermore, because the cooling section of the first disclosure is made of resin, the cooling unit has a greater degree of freedom in shape than conventional cooling units with metal cooling sections. Therefore, the cooling unit of the first disclosure can form a flow path to include a desired portion of the other surface of the base section corresponding to the portion where the electronic components are located, thereby enabling efficient cooling of heat generated by the electronic components. Furthermore, the cooling unit of the first disclosure has a structure in which the cooling section is formed by joining a cover section to the opening at the tip end of the peripheral wall section, allowing for easy molding without under-shaping during injection molding. Therefore, the cooling unit of the first disclosure can provide a lightweight cooling unit with a greater degree of freedom in shape and capable of being molded without under-shaping during injection molding.

[0019] The cooling unit of the second disclosure has the same effects as the cooling unit of the first disclosure, but further has the effect that, because it has a partition wall portion within the flow path, the outer shape of the peripheral wall portion can be made relatively simple, and the refrigerant can be caused to flow in the desired direction along the partition wall portion within the flow path, thereby enabling efficient cooling.

[0020] The cooling unit of the third disclosure has the effect of the cooling unit of the first or second disclosure, and further has the effect that a part of the peripheral wall fits into the fine irregularities formed on the other surface of the base where the base end side of the peripheral wall is joined, firmly joining the base and the peripheral wall, making it easier to prevent the refrigerant from leaking out from between the base and the peripheral wall.

[0021] The manufacturing method of the cooling unit of the fourth disclosure includes the peripheral wall portion forming process and the cooling portion forming process described above, and therefore it is possible to manufacture a cooling unit that can be made lighter, has a high degree of freedom in shape, and can be molded without becoming under-shaped during injection molding.

[0022] In the manufacturing method for a cooling unit of the fifth disclosure, in the peripheral wall forming step, a surface treatment is performed to form fine irregularities on the other surface of the base portion where the base end side of the peripheral wall is to be joined. Therefore, in addition to the effects of the manufacturing method for a cooling unit of the fourth disclosure, the manufacturing method for a cooling unit of the fifth disclosure further has the effect that a part of the material forming the peripheral wall portion penetrates into the fine irregularities formed on the other surface of the base portion where the base end side of the peripheral wall is to be joined, thereby firmly joining the base portion and the peripheral wall portion, thereby making it possible to obtain a cooling unit that is easy to prevent refrigerant from leaking out from between the base portion and the peripheral wall portion.

[0023] The method for manufacturing a cooling unit according to the sixth disclosure is the same as the method for manufacturing a cooling unit according to the fifth disclosure, except that the surface treatment is performed by laser processing. Therefore, in addition to the effects of the method for manufacturing a cooling unit according to the fifth disclosure, the method for manufacturing a cooling unit according to the sixth disclosure has the further effect that the laser processing can form finer micro-irregularities in precise positions, thereby firmly bonding the base portion and the peripheral wall portion.

[0024] In the method for manufacturing a cooling unit of the seventh disclosure, the peripheral wall and the cover are joined by vibration welding in the cooling portion forming step. Therefore, in addition to the effects of the method for manufacturing a cooling unit of any one of the fourth to sixth disclosures, the method for manufacturing a cooling unit of the seventh disclosure further has the effect of being able to firmly join the peripheral wall and the cover even when the cooling portion to be formed has a complex shape or a large shape.

[0025] The cooling unit manufacturing method of the eighth disclosure is the same as the cooling unit manufacturing method of the seventh disclosure, except that the protrusion is joined by vibration welding to form an inner space between the protrusion and the inner convex portion. Therefore, in addition to the effects of the cooling unit manufacturing method of the seventh disclosure, the cooling unit manufacturing method of the eighth disclosure has the effect that even if burrs are generated by vibration welding of the protrusion, the burrs are contained in the inner space formed between the protrusion and the inner convex portion, and therefore, the burrs can be prevented from falling into the flow path of the cooling unit.

[0026] The electronic device of the ninth disclosure has a cooling unit described in any one of the first to third disclosures, and therefore can be used to supply refrigerant from outside the case body to the flow path in the cooling unit and discharge the refrigerant that has circulated within the flow path to the outside of the case body, thereby efficiently cooling the heat generated by the electronic components.

[0027] The electronic device of the tenth disclosure has the above configuration, so that the refrigerant can be supplied from outside the case body through the supply pipe and the first connecting pipe into the flow path of the cooling unit, and the refrigerant that has circulated through the flow path can be discharged from the case body through the second connecting pipe and the discharge pipe. Therefore, the electronic device of the tenth disclosure can be used to supply the refrigerant from outside the case body to the flow path in the cooling unit and discharge the refrigerant that has circulated through the flow path to the outside of the case body, and can efficiently cool the heat generated by the electronic components.

[0028] FIG. 1 is a perspective view of a cooling unit according to an embodiment. FIG. 2 is a perspective view of a cooling unit according to an embodiment and a base used in a method for manufacturing the same, viewed from the other surface opposite the surface on which electronic components are arranged. FIG. 3 is an exploded perspective view of a cooling unit according to an embodiment, and a perspective view showing a state in which a pre-formed cover is joined to the tip opening of a peripheral wall joined to the other surface of the base in a method for manufacturing a cooling unit according to an embodiment. FIG. 4 is a perspective view of a cooling unit according to an embodiment, and a perspective view showing a state after a pre-formed cover is joined to the tip opening of a peripheral wall joined to the other surface of the base in a method for manufacturing a cooling unit according to an embodiment. FIG. 5 is a view showing the other surface of a cooling unit according to an embodiment and a base used in a method for manufacturing the same. FIG. 6 is a view showing a modified example of the other surface of the base in a cooling unit according to an embodiment and a method for manufacturing the same. FIG. 7 is a cross-sectional view of the cooling unit according to an embodiment shown in FIG. 4, taken along the line VII-VII. FIG. 8 is a partial enlarged view showing the circled portion in FIG. 7. Fig. 9 is a cross-sectional view showing a modified example of the shape of the cover used in the cooling unit and the manufacturing method thereof according to an embodiment, corresponding to Fig. 7. Fig. 10 is a perspective view of an electronic device according to an embodiment, in which a part of the side surface of the case body (specifically, the side surface on the front side) is cut away to allow the interior of the case body to be seen.

[0029] A cooling unit and a manufacturing method thereof according to an embodiment, and an electronic device according to an embodiment will be described with reference to FIGS.

[0030] 1 to 9, the cooling unit 1 of this embodiment has a base 2 and a cooling unit 3. The base 2 is formed in a flat plate shape, and an electronic component 41 (see FIG. 10 described later) can be arranged (mounted) on one surface 20a. Details of the electronic component 41 will be described in the section on electronic device 4 (described later).

[0031] The base 2 is made of metal and can be formed into a flat plate shape from various metal materials (the above-mentioned metals include alloys). Examples of metal materials that can form the base 2 include aluminum, aluminum alloys, iron, iron alloys, and stainless steel. In the cooling unit 1 of this embodiment, the metal material that forms the base 2 can be aluminum or an aluminum alloy, specifically, from the viewpoints of weight reduction, thermal conductivity, noise suppression, and the like.

[0032] The outer shape of the base 2 can be, for example, a rectangular shape, but is not particularly limited and can be appropriately selected depending on the shape of the electronic device 4 (described later) to which the cooling unit 1 is applied. Furthermore, the thickness of the base 2 can be, for example, 0.5 mm or more and 3 mm or less from the viewpoint of weight reduction, strength, etc.

[0033] 1 to 2, 5 and 6, a first through hole 21 and a second through hole 22 may be formed in the base 2, penetrating the base 2. The first through hole 21 and the second through hole 22 are both connected to a flow path 33 (described later) of the cooling unit 1. In this embodiment, the first through hole 21 is connected to one end of the flow path 33, and the second through hole 22 is connected to the other end of the flow path 33.

[0034] 2, 5 and 6, if necessary, a heat dissipation member such as a cooling fin 23 can be provided on the other surface 20b of the base 2 in a portion 201 corresponding to a portion 200 (see FIG. 10) where the electronic component 41 is disposed, in order to more efficiently dissipate heat from the electronic component 41. Examples of materials for the cooling fin 23 include aluminum, aluminum alloy, copper, copper alloy, iron, iron alloy, and ceramics.

[0035] As illustrated in FIGS. 1 and 4 , the cooling unit 3 is provided on the other surface 20b of the base unit 2. The cooling unit 3 uses a refrigerant (not shown) to cool the electronic components 41. The refrigerant may be liquid or gas. Preferably, the refrigerant is liquid from the viewpoints of chemical stability and a large specific heat. Examples of liquid refrigerants (liquid refrigerants) include water and LLC (Long Life Coolant). Examples of gaseous refrigerants (gas refrigerants) include fluorocarbons.

[0036] The cooling portion 3 is made of resin and can be formed into a desired shape using various resin materials. Examples of resin materials that can be used to form the cooling portion 3 include various thermoplastic resins such as polyamide (PA) such as polyamide 66, polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), and polypropylene (PP). In the cooling unit 1 of this embodiment, the resin material that forms the cooling portion 3 can be specifically polyamide such as polyamide 66 from the viewpoints of injection moldability, vibration weldability, and the like.

[0037] The cooling section 3 has a peripheral wall section 31, a cover section 32, and a flow path 33. The base end side of the peripheral wall section 31 is joined to the other surface 20b of the base section 2, and constitutes the outer peripheral side wall of the cooling section 3. The peripheral wall section 31 can be formed in an endless shape (seamless, cylindrical) with no joints in the circumferential direction. The peripheral wall section 31 has an opening 310 on the tip side, which is opposite the base end side of the base section 2.

[0038] The cover portion 32 is joined to the opening 310 of the peripheral wall portion 31 so as to close the opening 310. In the cooling unit 1 of this embodiment, the peripheral wall portion 31 and the cover portion 32 are preferably formed from the same material (polyamide in this example) from the viewpoints of bonding properties, vibration welding properties, and the like. The size and shape of the cover portion 32 are not particularly limited as long as it can close the opening 310 of the peripheral wall portion 31. Furthermore, as illustrated in FIGS. 3 and 4 , the cover portion 32 may be formed with a bulge portion 321 that bulges outward from the cover portion 32 along the flow path 33 from the viewpoint of improving refrigerant flow. Furthermore, if a partition wall portion 331 (described below) is provided within the flow path 33, the cover portion 32 may be formed with a recess 322 that serves as a portion to be joined to the tip surface of the partition wall portion 331. The recess 322 is a groove formed corresponding to the partition wall portion 331 when viewed from the outer surface of the cover portion 32. As shown in FIG. 9, the outer periphery of the cover portion 32 may be protruded toward the peripheral wall portion 31, and the protruding portion may be joinable to the peripheral wall portion 31.

[0039] As illustrated in Figures 3 to 4 and 7, the flow path 33 is a portion surrounded by the base portion 2 and the cooling portion 3, through which the refrigerant can flow. Specifically, the flow path 33 is formed by a space surrounded by the base portion 2, the peripheral wall portion 31 of the cooling portion 3, and the cover portion 32 of the cooling portion 3. However, as illustrated in Figures 2, 5 and 6, the flow path 33 is formed to include a portion 201 of the other surface 20b of the base portion 2 that corresponds to the portion 200 where the electronic component 41 is disposed. Note that the cooling fins 23 provided in the portion 201 of the other surface 20b of the base portion 2 that corresponds to the portion 200 where the electronic component 41 is disposed come into contact with the refrigerant within the flow path 33.

[0040] As illustrated in Fig. 3 and other figures, the cooling unit 1 of this embodiment can have a partition wall portion 331 in the flow path 33 to separate the flow path 33. Similar to the peripheral wall portion 31, the partition wall portion 331 has a base end joined to the other surface 20b of the base portion 2. Here, an example is shown in which the partition wall portion 331 is formed to protrude from the base portion 2, but the partition wall portion 331 may also be formed to protrude from the cover portion 32. Note that one or more partition wall portions 331 can be provided.

[0041] Furthermore, in the cooling unit 1 of this embodiment, a partition wall 331 is provided in the flow path 33, so that the refrigerant flows from one end to the other end of the flow path 33, as indicated by the symbol Y in FIG. 5 . The partition wall 331 is not necessarily required in the flow path 33. For example, as illustrated in FIG. 6 , the partition wall 331 may be omitted, and a portion 24 to which the peripheral wall 31 is joined may be formed on the other surface 20b of the base 2, corresponding to a portion 200 where the electronic component 41 is disposed, so that the refrigerant flows to that portion. Note that in FIGS. 5 and 6 , the peripheral wall 31 and the partition wall 331 are omitted and not shown, but only the portion 24 to which the peripheral wall 31 is joined (a portion 240 to which the base end of the peripheral wall 31 is to be joined) and the portion 25 to which the partition wall 331 is joined (a portion 250 to which the base end of the partition wall 331 is to be joined) are shown.

[0042] 5 and 6, in the cooling unit 1 of this embodiment, fine irregularities (not shown) are formed on a portion 24 of the other surface 20b of the base 2 to which the peripheral wall 31 is joined (i.e., before the peripheral wall 31 is joined, this is a portion 240 to which the base end side of the peripheral wall 31 is to be joined). When the partition wall 331 is formed, fine irregularities may also be formed on a portion 25 of the other surface 20b of the base 2 to which the partition wall 331 is joined (i.e., before the partition wall 331 is joined, this is a portion 250 to which the base end side of the partition wall 331 is to be joined), as shown in FIG.

[0043] The cooling unit 1 of this embodiment has a resin cooling section 3 provided on the other surface 20b of the metal base 2, thereby enabling a lighter weight than conventional cooling units in which the cooling section 3 is made of metal. Furthermore, the cooling unit 1 of this embodiment has a resin cooling section 3, allowing for greater freedom in design compared to conventional cooling units in which the cooling section 3 is made of metal. Therefore, the cooling unit 1 of this embodiment can form the flow path 33 to include a desired portion 201 on the other surface 20b of the base 2 that corresponds to the portion 200 where the electronic component 41 is located, thereby enabling efficient cooling of heat generated by the electronic component 41. Furthermore, the cooling unit 1 of this embodiment has a structure in which the cover 32 is joined to the opening 310 on the tip side of the peripheral wall 31, thereby enabling easy molding without undercutting during injection molding.

[0044] Therefore, according to the cooling unit 1 of this embodiment, it is possible to provide a cooling unit 1 that can be made lighter, has a high degree of freedom in shape, and can be molded without becoming under-shaped during injection molding.

[0045] (Method for Manufacturing a Cooling Unit) The method for manufacturing a cooling unit of this embodiment is a method for manufacturing a cooling unit that is formed in a flat plate shape and has a metal base portion on one surface of which electronic components can be placed, and a resin cooling portion that is provided on the other surface of the base portion and uses a refrigerant to cool the electronic components. Here, the manufacturing of the cooling unit 1 of this embodiment described above will be used as an example and will be described with appropriate reference to FIGS.

[0046] The method for manufacturing a cooling unit of this embodiment includes a peripheral wall forming step and a cooling portion forming step.

[0047] In the manufacturing method of the cooling unit of this embodiment, the peripheral wall forming step is a step of injection molding a peripheral wall 31 having an opening 310 at its distal end onto the other surface 20b of the base 2 and joining the base end of the peripheral wall 31, as illustrated in Figures 2 and 3 . Specifically, outsert molding can be used as the injection molding method. Because the peripheral wall 31 having the opening 310 at its distal end does not have an under-shaped configuration, the peripheral wall 31 can be easily formed and joined to the base 2 by an injection molding method such as outsert molding.

[0048] 5 and 6, in the peripheral wall forming step, it is preferable to perform a surface treatment to form fine irregularities on a portion 240 of the other surface 20b of the base 2 where the base end side of the peripheral wall 31 is to be joined. This is because, when the peripheral wall 31 is injection molded, part of the material forming the peripheral wall enters the fine irregularities, thereby enabling the base 2 and the peripheral wall 31 to be firmly joined together.

[0049] The surface treatment for forming the fine irregularities is preferably performed by laser processing, because it is possible to form finer irregularities at precise positions by applying a laser to the portion 240 where the base end side of the peripheral wall portion 31 is to be joined. The surface treatment for forming the fine irregularities may be, other than laser processing, surface treatment such as blasting, etching, plasma discharge processing, or alumite processing.

[0050] In the manufacturing method of the cooling unit of this embodiment, the cooling portion forming process is a process of forming a cooling portion 3 having a peripheral wall portion 31 and a cover portion 32 by joining a cover portion 32, which is pre-formed in a shape that can cover the opening 310 of the peripheral wall portion 31, to the opening 310, as illustrated in Figures 3 and 4, etc.

[0051] In this cooling portion forming step, a flow path 33 through which a refrigerant can flow is formed, surrounded by the base portion 2 and the cooling portion 3. However, the flow path 33 is formed so as to include a portion 201 of the other surface 20b of the base portion 2 that corresponds to a portion 200 where the electronic component 41 is arranged.

[0052] The peripheral wall portion 31 and the cover portion 32 are preferably joined by vibration welding. This is because the peripheral wall portion 31 and the cover portion 32 can be firmly joined together even when the cooling portion 3 to be formed has a complex or large shape. The method of joining the peripheral wall portion 31 and the cover portion 32 may be, other than vibration welding, for example, heat welding, ultrasonic welding, or bonding with an adhesive.

[0053] Specifically, when joining the peripheral wall portion 31 and the cover portion 32 by vibration welding, it is preferable to carry out the process as follows. That is, as illustrated in Figures 7 and 8, at least one of the surface of the peripheral wall portion 31 that is to be joined with the cover portion 32 and the surface of the cover portion 32 that is to be joined with the peripheral wall portion 31 is protruded to form a protrusion 34. Figures 7 and 8 illustrate a case in which the protrusion 34 includes both a peripheral wall portion-side protrusion 341 that is formed by protruding the surface of the peripheral wall portion 31 that is to be joined with the cover portion 32, and a cover portion-side protrusion 342 that is formed by protruding the surface of the cover portion 32 that is to be joined with the peripheral wall portion 31.

[0054] Furthermore, an inner convex portion 35 is formed on at least one of the peripheral wall portion 31 and the cover portion 32 at an inward position closer to the flow path 33 than the protrusion 34. In Figures 7 and 8, the inner convex portion 35 includes both a peripheral wall portion-side inner convex portion 351 formed on the peripheral wall portion 31 and a cover portion-side inner convex portion 352 formed on the cover portion 32 at an inward position closer to the flow path 33 than the protrusion 34.

[0055] 7 and 8, an outer-side convex portion 36 may be formed on at least one of the peripheral wall portion 31 and the cover portion 32 at a position outward from the protrusion 34. In FIGS. 7 and 8, the outer-side convex portion 36 is exemplified by a peripheral-wall-side outer convex portion 361 formed on the peripheral wall portion 31 at a position outward from the protrusion 34. Although not shown, the outer-side convex portion 36 may also be formed by a cover-side outer convex portion formed on the cover portion 32 at a position outward from the protrusion 34.

[0056] As illustrated in FIGS. 7 and 8 , vibration welding is performed at the protrusion 34, whereby the peripheral wall protrusion 341 and the cover protrusion 342 are joined (vibration welded) to form a joint margin (which can also be referred to as a welding margin) 39. An inner space 37 is formed between the protrusion 34 and the inner convex portion 35. Here, an outer space 38 is also formed between the protrusion 34 and the outer convex portion 36. Even if burrs (not shown) are generated when the peripheral wall 31 and the cover 32 are vibration welded, the generated burrs are contained in the inner space 37 and the outer space 38. Therefore, the presence of the inner space 37 can prevent burrs from falling into the cooling section 3, specifically, into the flow path 33. The presence of the outer space 38 can prevent burrs from falling out of the cooling section 3.

[0057] The inner and outer protrusions 35 and 36 are preferably formed to have lengths such that they do not abut against the surfaces facing the tip surfaces of the inner and outer protrusions 35 and 36 after vibration welding at the protrusions 34. This is to join the peripheral wall protrusions 341 and the cover protrusions 342 and ensure reliable vibration welding at the protrusions 34. As illustrated in FIGS. 7 and 8 , after vibration welding at the protrusions 34, the tip surfaces of the peripheral wall protrusions 351 and the cover protrusions 352 do not abut, leaving a slight gap between the respective tip surfaces. Similarly, the tip surface of the peripheral wall protrusion 361 does not abut against the opposing surface 362 of the cover 32 that faces the tip surface of the peripheral wall protrusion 361, leaving a slight gap between the respective surfaces.

[0058] The manufacturing method of the cooling unit of this embodiment includes the peripheral wall portion forming process and the cooling portion forming process described above, and therefore it is possible to manufacture the cooling unit 1 of this embodiment, which can be made lightweight, has a high degree of freedom in shape, and can be molded without becoming under-shaped during injection molding.

[0059] (electronic equipment)

[0060] As shown in FIG. 10, the electronic device 4 of this embodiment includes the cooling unit 1 of this embodiment, an electronic component 41, and a case body 42.

[0061] The electronic component 41 is disposed on one surface 20a of the base 2 of the cooling unit 1. While Fig. 10 shows an example in which a plurality of electronic components 41 (specifically, two) are mounted inside the case body 42, the number of electronic components 41 is not particularly limited. It can be selected appropriately depending on the type, specifications, etc. of the electronic device 4. In Fig. 10, the electronic component 41 is shown in a simplified form to make it easier to illustrate the configuration other than the electronic component 41, and the size and shape of the electronic component 41 depicted in Fig. 10 differ from those of the actual product.

[0062] Examples of the electronic component 41 include a reactor, a coil, an inverter, and a semiconductor. These components can be used alone or in combination of two or more. Among the electronic components 41, a reactor, a coil, an inverter, a semiconductor, and the like generate heat and reach high temperatures, and are therefore suitable as the electronic component 41 to be disposed on one surface 20 a of the base portion 2.

[0063] The case body 42 accommodates the cooling unit 1 therein. Specifically, the case body 42 has a case bottom 421, case side surfaces 422 extending from the outer periphery of the case bottom 421, and a case top 423 that closes an upper opening formed by the case side surfaces 422. The case side surfaces 422 are formed in a rectangular cylindrical shape as a whole. Note that the front portion of the case side surfaces 422 is omitted in FIG. 10. Such a case body 42 can be formed, for example, by integrally molding the case bottom surface 421 and the case side surfaces 422 using aluminum die casting or the like, and then covering the case top surface 423.

[0064] In the electronic device 4 illustrated in Figure 10, the inside of the case body 42 is partitioned by the base part 2 of the cooling unit 1, and the electronic component 41 is arranged in an upper space 425 inside the case surrounded by the inner wall surface 424 of the case body 42 and one surface 20a of the base part 2, and the cooling part 3 is arranged in a lower space 426 inside the case surrounded by the inner wall surface 424 of the case body 42 and the other surface 20b of the base part 2.

[0065] The electronic device 4 is configured to supply refrigerant from outside the case body 42 to the flow path 33 in the cooling unit 1, and to be able to discharge the refrigerant that has flowed through the flow path 33 to the outside of the case body 42. In the electronic device 4 of this embodiment, as illustrated in Fig. 10, the electronic device 4 further includes a supply pipe 43, a discharge pipe 44, a first connecting pipe 45, and a second connecting pipe 46.

[0066] The supply pipe 43 is connected to the outer surface of the case body 42 and is used to supply refrigerant to the case body 42. The discharge pipe 44 is connected to the outer surface of the case body 42 and is used to discharge refrigerant from the case body 42. In the electronic device 4 of this embodiment, as illustrated in FIG. 10 , the supply pipe 43 is connected to a supply pipe through hole 430 formed in the case side surface 422 by fitting it from the outside of the case side surface 422. The discharge pipe 44 is connected to a discharge pipe through hole 440 formed in the case side surface 422 by fitting it from the outside of the case side surface 422. In the electronic device 4 of this embodiment, the supply pipe 43 and the discharge pipe 44 are connected to one of the multiple (specifically, four) case side surfaces 422, and it is possible to supply and discharge refrigerant on the side of this one case side surface 422.

[0067] The first connecting pipe 45 is provided inside the case body 42, specifically in the upper case space 425. The first connecting pipe 45 connects the supply pipe 43 to a first through hole 21 formed in the base portion 2 of the cooling unit 1 and communicating with the flow path 33 of the cooling unit 1. The first connecting pipe 45 and the supply pipe 43, and the first connecting pipe 45 and the first through hole 21 are connected by being fitted together.

[0068] Similarly, the second connecting pipe 46 is provided inside the case body 42, specifically in the upper case space 425. The second connecting pipe 46 connects the exhaust pipe 44 to a second through hole 22 formed in the base portion 2 of the cooling unit 1 and communicating with the flow path 33 of the cooling unit 1. The second connecting pipe 46 and the exhaust pipe 44, and the second connecting pipe 46 and the second through hole 22 are connected by being fitted together.

[0069] In the electronic device 4 of this embodiment, the refrigerant supplied to the supply pipe 43 from a refrigerant supply source (not shown) flows through the first connecting pipe 45 and enters the flow path 33 in the cooling section 3 of the cooling unit 1 through the first through-hole 21. The refrigerant that has entered the flow path 33 flows through the inside of the flow path 33, enters the second connecting pipe 46 through the second through-hole 22, flows through the second connecting pipe 46, and is discharged from the discharge pipe 44.

[0070] As described above, the electronic device 4 of this embodiment can supply the refrigerant from the outside of the case body 42 into the flow path 33 of the cooling unit 1 through the supply pipe 43 and the first connecting pipe 45, and can also discharge the refrigerant that has circulated through the flow path 33 from the case body 42 through the second connecting pipe 46 and the discharge pipe 44. Therefore, the electronic device 4 of this embodiment can efficiently cool the heat generated by the electronic components 41.

[0071] Examples of the electronic device 4 include a power control unit (PCU) and an electronic control unit (ECU) in an automobile, etc. In this case, the electronic device 4 can be installed in the engine compartment or the interior of the automobile.

[0072] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the present disclosure. For example, in the above-described embodiments, the first through hole 21 and the second through hole 22 are formed in the base portion 2 of the cooling unit 1. However, the first through hole 21 and the second through hole 22 may be formed in the peripheral wall portion 31 to supply and discharge the refrigerant. In addition, in the above-described embodiments, the first connecting pipe 45 and the second connecting pipe 46 are provided in the upper case interior space 425. However, the first connecting pipe 45 and the second connecting pipe 46 may also be provided in the lower case interior space 426. Furthermore, the configurations described in the above-described embodiments can be combined with each other in any desired manner. Furthermore, the claims as originally filed can be combined with each other in any desired manner.

Claims

1. A cooling unit having: a metal base portion formed in a flat plate shape and capable of arranging electronic components on one surface; and a resin cooling portion provided on the other surface of the base portion for cooling the electronic components using a refrigerant, wherein the cooling portion has a peripheral wall portion whose base end is joined to the other surface of the base portion and which has an opening on its tip end; and a cover portion joined to the opening of the peripheral wall portion so as to close the opening, and the cooling unit is surrounded by the base portion and the cooling portion and has a flow path through which the refrigerant can flow, including a portion of the other surface of the base portion corresponding to the portion on which the electronic components are arranged.

2. The cooling unit according to claim 1, wherein the flow path has a partition wall portion for dividing the inside of the flow path.

3. The cooling unit according to claim 1, wherein fine irregularities are formed on the other surface of the base portion at a portion where the peripheral wall portion is joined.

4. A method for manufacturing a cooling unit having a metal base portion formed in a flat plate shape and capable of arranging electronic components on one surface thereof, and a resin cooling portion provided on the other surface of the base portion and for cooling the electronic components using a refrigerant, the method comprising: a peripheral wall portion forming step of injection molding a peripheral wall portion having an opening on a tip side onto the other surface of the base portion and joining the base end side of the peripheral wall portion; and a cooling portion forming step of joining a cover portion pre-formed in a shape capable of closing the opening of the peripheral wall portion to the opening, thereby forming the cooling portion having the peripheral wall portion and the cover portion, wherein in the cooling portion forming step, a flow path is formed that is surrounded by the base portion and the cooling portion and allows the refrigerant to flow through, and includes a portion of the other surface of the base portion that corresponds to the portion where the electronic components are arranged.

5. A method for manufacturing a cooling unit as described in claim 4, wherein in the peripheral wall portion forming step, a surface treatment is performed to form fine irregularities on the other surface of the base portion, on the portion where the base end side of the peripheral wall portion is to be joined.

6. The method for manufacturing a cooling unit according to claim 5, wherein the surface treatment is performed by laser processing.

7. A method for manufacturing a cooling unit according to any one of claims 4 to 6, wherein in the cooling portion forming step, the peripheral wall portion and the cover portion are joined by vibration welding.

8. A method for manufacturing a cooling unit as described in claim 7, wherein at least one of a surface of the peripheral wall portion to be joined with the cover portion and a surface of the cover portion to be joined with the peripheral wall portion is protruded to form a protrusion, and an inner convex portion is formed on at least one of the peripheral wall portion and the cover portion at a position inwardly closer to the flow path than the protrusion, and an inner space is formed between the protrusion and the inner convex portion by joining the protrusion by vibration welding.

9. An electronic device comprising: a cooling unit according to any one of claims 1 to 3; an electronic component arranged on one surface of the base portion of the cooling unit; and a case body that houses the cooling unit, wherein the refrigerant is supplied to the flow path in the cooling unit from outside the case body, and the refrigerant that has circulated within the flow path can be discharged to the outside of the case body.

10. An electronic device comprising: a cooling unit according to any one of claims 1 to 3; the electronic component arranged on one surface of the base part of the cooling unit; a case body accommodating the cooling unit therein; a supply pipe connected to the outer surface of the case body for supplying the refrigerant to the case body; a discharge pipe connected to the outer surface of the case body for discharging the refrigerant from the case body; a first connecting pipe provided within the case body for connecting the supply pipe to a first through hole formed in the base part of the cooling unit and communicating with the flow path of the cooling unit; and a second connecting pipe provided within the case body for connecting the discharge pipe to the second through hole formed in the base part of the cooling unit and communicating with the flow path of the cooling unit.

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