Rod-like fin-shaped heat sink, method for manufacturing same, and cooling device mounted with heat sink

Abstract

The purpose of the present invention is to provide a rod-like fin-shaped heat sink capable of more quickly and intensively collecting cooling capacity necessary for cooling a plurality of electronic element packages in an area where it is required, and saving energy.　This rod-like fin-shaped heat sink (12) is provided with a first rod-like fin (221) and a second rod-like fin (222), and a base part (20) in which the rod-like fins are erected. The base part (20) has a second surface (20L) facing a first surface (20U) in contact with the plurality of electronic element packages in a back-to-back manner. In the second surface (20L), a plurality of cooling areas (C1-C3) for cooling each of the plurality of electronic element packages are set in a column along a predetermined direction (Y) in which a cooling fluid (FL) flows. In each of the plurality of cooling areas (C1-C3), fin assemblies (G1-G3) comprising the first rod-like fin (221) are erected on the basis of the cooling capacity required for each of the plurality of electronic element packages. A side area (EL, ER) is set on both sides of the second surface (20U) in a lateral direction (X), and the second rod-like fin (222) for energizing and controlling the flow of the fluid (FL) so that the cooling fluid (FL) inputted via an inlet area (IT) is directed to the cooling areas (C1-C3) is erected in each side area.

Description

Rod-shaped fin heat sink, its manufacturing method, and cooling device equipped with the heat sink

[0001] The present invention relates to a rod-shaped fin heat sink and a manufacturing method thereof, as well as a cooling device equipped with the heat sink, and in particular to a rod-shaped fin heat sink equipped with rod-shaped fins that forcibly cools electronic elements that generate heat during operation, as well as a manufacturing method thereof, and a cooling device equipped with the heat sink.

[0002] In recent years, systems that control large amounts of power, such as drive circuits and control circuits, have become widespread, particularly in fields such as electric vehicles (EVs), hybrid vehicles, aircraft, home appliances, communication devices, and industrial equipment. Along with this widespread use, power semiconductors (power diodes and power transistors), which are semiconductor elements that handle high voltages and large currents to control and convert this power, have come to play an important role. These power semiconductors are often packaged and incorporated into circuits such as inverters, converters, AC / AC converters, and DC / DC converters.

[0003] Semiconductor packages play such an important role in that they use a heat sink, either natural or forced, to cool the semiconductor package and use it in contact with the package as a way to suppress the temperature rise caused by heat generated during operation. These heat sinks come in a variety of structures and types, and designers select the appropriate type to suit the amount of heat generated by the semiconductor package and the cooling environment when carrying out thermal design.

[0004] A structure for simultaneously cooling multiple semiconductor modules under such circumstances is exemplified in Patent Document 1 (JP 2020-92250 A). Patent Document 1 shows a heat sink that employs pin fins with a roughly diamond-shaped cross section, in which three semiconductor units, such as a three-phase inverter with U, V, and W phases, are arranged in parallel and a refrigerant is supplied from and passes through the same cooling source.

[0005] According to this patent document, circuit boards for three-phase semiconductor modules (units) (U, V, and W phases) are mounted in contact with one surface of a base plate, and a fin area is provided on the other surface, large enough to encompass the combined area of ​​the three circuit boards. A series of rod-shaped cooling pin fins, each with a diamond cross section and elongated in the vertical direction, are integrally provided on the surface of the base plate at a predetermined uniform density throughout the fin area. The space in which the cooling pin fins are provided is enclosed by a thin, approximately rectangular parallelepiped wall. A refrigerant is fed into the enclosed space through an input port located on one side at one longitudinal end, flows through the enclosed space, and is discharged through an output port located on the other side at the other longitudinal end.

[0006] JP 2020-92250 A

[0007] However, while the heat sink described in the aforementioned Patent Document 1 is capable of simultaneously cooling multiple semiconductor modules, in reality, the diamond-shaped pin fins are evenly and uniformly arranged in a single fin area at the same density. Although the pin fins themselves are designed to increase surface area, the energy required for cooling is still large. In other words, cooling one entire fin area cools three semiconductor modules mounted on the surface opposite that fin area. Conversely, the cooling capacity required to cool three semiconductor packages must be provided to the entire fin area. As can be seen from the diagram in Patent Document 1, the three semiconductor packages are mounted separately from each other, and cooling energy must also be applied to these separate areas.

[0008] In addition, the heat sink described in Patent Document 1 has a refrigerant inlet and outlet positioned diagonally opposite each other with respect to a rectangular group of pin fins evenly arranged in a plan view. As a result, the refrigerant that flows in through the inlet at a specified pressure seeps through the spaces between the pin fins and flows out through the outlet, but it takes a long time for this flow to reach a steady state. In other words, the time constant until thermal equilibrium is reached is large, and the thermal energy also increases accordingly.

[0009] Furthermore, even if a state of thermal equilibrium is reached as described above, variations in cooling capacity tend to occur between the pin fins erected at the corners and those erected near the center.

[0010] In view of the above, it has been necessary to further reduce energy consumption while meeting the required cooling capacity for a plurality of semiconductor packages.

[0011] For this reason, it is desirable to provide a rod-shaped fin heat sink and a manufacturing method thereof, as well as a cooling device equipped with such a heat sink, which can provide the cooling capacity required to cool multiple semiconductor packages more quickly and intensively to the area where it is needed, while also achieving energy savings.

[0012] The heat sink according to the present disclosure is provided as a rod-fin type heat sink that dissipates heat generated from a package enclosing an electronic element such as a power semiconductor in association with the operation of the electronic element by heat exchange with a forcibly supplied cooling fluid. This rod-fin type heat sink includes first and second rod-shaped fins having thermal conductivity, and a thermally conductive base portion on which the first and second rod-shaped fins are erected.

[0013] The base portion is capable of contacting a plurality of the packages and has a first surface that absorbs the heat generated by the electronic elements and a second surface that faces back to back to the first surface and to which the heat is transferred.

[0014] Also, on the second surface, a plurality of cooling areas for cooling each of the plurality of packages are arranged in a vertical row along a predetermined direction in which the input cooling fluid flows.

[0015] In each of the plurality of cooling areas, a fin assembly consisting of a plurality of the first rod-shaped fins is provided based on the cooling capacity required for each of the plurality of packages. Furthermore, on the second surface, side areas adjacent to the plurality of cooling areas are set on both sides in a lateral direction intersecting the passing direction.

[0016] A plurality of second rod-shaped fins are erected in each of the side areas on both sides to control the flow of the cooling fluid that enters through the inlet area so that the cooling fluid is directed toward the plurality of cooling areas.

[0017] A cooling device including the rod-fin heat sink is also provided, which includes a fluid circulation means for circulating the cooling fluid through the rod-fin heat sink to exchange heat between the rod-fins of the heat sink and the cooling fluid.

[0018] Also provided as a typical example according to the aspects of the present disclosure is a method for manufacturing the rod fin heat sink described above.

[0019] This manufacturing method is characterized by comprising: a first step of setting a pin alignment jig, which has a plurality of through holes formed therein that match the diameters and erect positions of the plurality of rod-shaped fins, on the base portion so as to face the second surface, and inserting the plurality of rod-shaped fins into the plurality of through holes so that one end of each of the plurality of rod-shaped fins protrudes from the plurality of through holes; a second step of setting a pressure jig that applies pressure between the first surface of the base portion and one end of each of the plurality of rod-shaped fins protruding from the plurality of through holes in the pin alignment jig; a third step of diffusion bonding or brazing the other end of each of the plurality of pins to the second surface of the base portion while applying pressure with the pressure jig; and a fourth step of removing the pin alignment jig from the plurality of rod-shaped fins after the third step.

[0020] According to the present disclosure, there are provided a rod-fin heat sink that dissipates heat generated from a package enclosing an electronic element due to the operation of the electronic element through heat exchange between a forcibly supplied cooling fluid and thermally conductive rod-shaped fins, a method for manufacturing the same, and a cooling device equipped with the rod-fin heat sink.

[0021]

[0022] FIG. 1 is a schematic diagram illustrating a rod-fin heat sink according to a first embodiment and a cooling device incorporating the same. FIG. 2 is a plan view illustrating the schematic configuration of the upper surface of the heat sink as viewed along line A-A' in FIG. 1. FIG. 3 is a plan view illustrating the schematic configuration of the lower surface of the heat sink as viewed along line B-B' in FIG. 1. FIG. 4 is an enlarged partial view of a local portion Gin in FIG. 3, illustrating the shape, size, and positional relationship of the rod-fins. FIG. 5 is a system configuration diagram of a cooling device. FIG. 6 is a graph conceptually illustrating the cooling capacity consumed by each cooling area in a rod-fin heat sink according to the present disclosure, which has multiple cooling areas arranged in a vertical row. FIG. 7 is a plan view illustrating the schematic configuration of the lower surface (one side) of a rod-fin heat sink according to a second embodiment. FIG. 8 is a plan view illustrating the schematic configuration of the lower surface (one side) of a rod-fin heat sink according to Modification 1. FIG. 9 is a plan view illustrating the schematic configuration of the lower surface (one side) of a rod-fin heat sink according to Modification 2. FIG. 10 is a plan view illustrating the schematic configuration of the underside (one side) of a rod-fin heat sink according to Variation 3, showing two semiconductor packages arranged in a vertical line. FIG. 11 illustrates a schematic configuration of a rod-fin heat sink according to Variation 4 (FIG. 11A), a schematic plan view along line A-A' (FIG. 11B), and a schematic plan view along line B-B' (FIG. 11C). FIG. 12 is a plan view illustrating the schematic configuration of the underside (one side) of a rod-fin heat sink according to Variation 5. FIG. 13 illustrates Variation 6, particularly illustrating the inverted trapezoidal fin cross sections along lines C-C' and D-D' shown in FIG. 7. FIG. 14 illustrates Variation 7, particularly illustrating a different positional relationship between the input and output ports and a configuration in which the flow paths are not linear. FIG. 15 illustrates Variation 8, showing an example of a rod-fin arrangement with a change in flow path direction. FIG. 16 illustrates Variation 9, showing another example of a rod-fin arrangement with a change in flow path direction. Fig. 17 is a flowchart outlining a method for manufacturing a rod-fin heat sink according to the third embodiment. Fig. 18 is a diagram illustrating components required in each step of the manufacturing method. Fig. 19 is a diagram outlining each step of the manufacturing method.FIG. 20 illustrates the corrosion protection structure according to the tenth modification, and also illustrates the corrosion protection of the base plate and the rod-shaped fins.

[0023] First Embodiment First, based on FIGS. 1 to 6, the basic (conceptual) configuration and effects of a rod-fin heat sink according to the present disclosure will be described as a first embodiment, along with modifications thereof.

[0024] Fig. 1 shows the basic structure of the rod-shaped fin heat sink according to the first embodiment. The configuration shown in Fig. 1 is a side perspective view illustrating the schematic configuration of a cooling device 1 that cools three semiconductor packages PK1, PK2, and PK3 (also simply called packages or modules), each of which packages three power semiconductors used in a control circuit of a drive motor mounted in an EV or the like.

[0025] The three semiconductor packages PK1, PK2, and PK3 may be, for example, packages of inverter circuits for the U, V, and W phases that control a single three-phase AC motor. In this case, the cooling capacity required to dissipate heat generated from the electric circuits (including power semiconductors (electronic elements) that switch large currents) of the three semiconductor packages PK1, PK2, and PK3 is usually the same.

[0026] Of course, the three semiconductor packages PK1, PK2, and PK3 may be semiconductor packages mounted on different types of electronic circuits. In this case, at least some of the cooling capacities required for the three semiconductor packages PK1, PK2, and PK3 may differ from those of the remaining packages. When the cooling capacities are different, the three semiconductor packages may be referred to as three "types" of semiconductor packages.

[0027] The rod-shaped fin heat sink of the present disclosure is intended for a structure in which multiple packages containing electrical elements such as semiconductor elements (including power semiconductors) that need to be cooled to generate heat during operation are arranged in a vertical row, and has a basic feature in that it can cool multiple packages "at once" with a single heat sink.

[0028] For this reason, the number of packages mounted on one heat sink is two or more; here, three semiconductor packages are given as a representative example, but of course it may also be two semiconductor packages or four or more semiconductor packages, such as power semiconductors.

[0029] <Details of Cooling Device and Heat Sink> The cooling device 1 shown in FIG. 1 will now be described in detail.

[0030] This cooling device 1 employs a forced cooling system that forcibly circulates a cooling fluid such as cooling water, cooling air, or a refrigerant (e.g., chlorofluorocarbon gas). Note that since such forced cooling structures are known, the description of such structures will be simplified.

[0031] As shown in FIG. 1 , the cooling device 1 includes a rod-fin heat sink 12 (hereinafter also referred to simply as a heat sink, including a heat sink body 30, which will be described later) on which multiple (types of) power semiconductor packages (hereinafter also referred to simply as semiconductor packages) PK1, PK2, and PK3 are mounted in contact with one surface of the rod-fin heat sink 12. The cooling device 1 also includes a substantially box-shaped cover 14 that is disposed opposite the rod-fin heat sink 12 to encompass the rod-fin heat sink 12 and define a cooling space SP through which a cooling fluid FL flows. The cooling device 1 also includes an input port 16A and an output port 16B on opposite sides of a side surface 14A of the cover 14 that face each other in the fluid flow direction (the Y-axis direction in FIG. 1 ) through which the cooling fluid FL flows, a pipe 18 connecting the ports 16A and 16B, and a fluid supply device (fluid source) 19 inserted midway through the pipe 18.

[0032] The heat sink 12 has a function of receiving heat from the semiconductor packages PK1, PK2, and PK3, and includes a base plate (base portion) 20 that is rectangular in plan view (e.g., rectangular: see FIGS. 2 and 3 ), and a plurality of rod-like fins 22 (also called pin fins) that are classified as long, thin, rod-like cooling fins and are provided upright on the base plate 20. In particular, when attention is focused on a unit consisting only of the base plate 20 and the plurality of rod-like fins 22, this unit is called a heat sink main body.

[0033] In this embodiment, as shown in Fig. 3, the rod-shaped fins 22 (pin fins) used are two types of rod-shaped fins with different cross-sectional shapes, namely, a first rod-shaped fin 221 and a second rod-shaped fin 222, whose cross-sectional shapes in the horizontal direction (direction of the XY plane) intersecting with the length direction (Z-axis direction (height direction) when erected: see Fig. 1) are elliptical, rectangular, and circular. For convenience of explanation, these first and second rod-shaped fins 221, 222 will also be collectively referred to simply as rod-shaped fins 22 (: 221, 222).

[0034] The base plate 20 and the rod-shaped fins 22 (: 221, 222) are both formed of a metal material with high thermal conductivity, such as aluminum or an aluminum alloy (hereinafter simply referred to as "aluminum" or "aluminum"), or copper or a copper alloy (hereinafter simply referred to as "copper"). In this embodiment, the base plate 20 and the multiple rod-shaped fins 22 are prepared as separate components, and the two are joined together by, for example, brazing or diffusion bonding to form the main part of the heat sink 12.

[0035] In addition, when the base plate 20 and the rod-shaped fins 22 are both formed of copper or a copper alloy and the cover 14 is made of aluminum, from the standpoint of corrosion prevention, at least the portion of the base plate 20 that abuts the cover 14, the rod-shaped fins 22, and the surface of the aluminum cover 14 that is exposed to the cooling space SP are subjected to a corrosion-resistant surface treatment, for example, nickel plating.

[0036] The base plate 20 and the rod-like fins 22 may be made of different materials (for example, aluminum and copper, aluminum and brass, etc.).

[0037] For convenience of explanation, the short-side direction of the rectangular base plate 20 is taken as the X-axis, and the Y-axis and Z-axis perpendicular to this X-axis are set as shown in Figures 1 to 3. In other words, the longitudinal direction of the base plate 20 is the Y-axis direction, which corresponds to the direction in which the cooling fluid FL flows through the cooling space SP (passing direction (defined as a predetermined direction)), and the height (thickness) direction corresponds to the Z-axis direction.

[0038] Although the X, Y, and Z directions define physical directions relative to the base plate 20, the flow of the cooling fluid FL does not necessarily coincide with these physical directions. In this embodiment, as described below, a structure in which multiple cooling areas are arranged in a vertical column is adopted, and the fluid FL is intended to pass in this vertical column direction. Therefore, when describing the flow of the fluid FL, the flow direction Y (roughly corresponding to the Y-axis direction) and the board longitudinal direction Y are also referred to, but both refer to the same direction. Similarly, the horizontal direction X (roughly corresponding to the X-axis direction) that intersects the flow direction Y is also referred to. Furthermore, the term "vertical column" referred to in this embodiment means that the areas and fins are lined up vertically in one direction (vertical column), similar to parallel parking of a vehicle.

[0039] Furthermore, as shown in the figure, the Z-axis direction is taken as a direction from the upper surface of the base plate 20 (the surface on which the semiconductor package is abutted and placed) to the lower surface (the surface on which the multiple rod-shaped fins 22 are erected).

[0040] In this embodiment, the rod-shaped fins 22 (221, 222) are classified as "fins having a rod shape that is elongated in the vertical direction relative to the size of the fin's horizontal cross section" (also simply referred to as pin fins). The rod-shaped fins 22 have both ends (a tip end 22T and a bottom end 22R in the Z-axis direction in FIG. 1 ) in the longitudinal direction LE (Z-axis direction) of the rod-shaped fin 22 itself. Note that "rod-shaped" refers to "an elongated, straight, or almost straight shape," which is the usual concept of "an elongated, straight shape." The shape of the cross section may differ, and the fin does not necessarily have to be a perfect rod shape. Even if the elongated shape is somewhat irregular, it is understood to be "rod-shaped" as long as it is close to "an elongated, straight, or almost straight shape."

[0041] The size of the cross section in the horizontal direction (direction along the XY plane) perpendicular to the longitudinal direction LE may be constant regardless of the position in the height direction of the cross section, or conversely, the size may be formed so that the cross section becomes larger as the position approaches the tip end 22T. In the latter case, in the upright state, the tip end 22T has a thicker inverted triangular cross section than the lower end 22R.

[0042] The rod-like fins 22 may have a round rod shape as a whole, a prismatic shape with a quadrangular (rectangular) cross section, or a triangular prism shape with a triangular cross section.Similarly, they may have a polygonal prism shape with pentagons or more.

[0043] In the case of a fin whose cross section in the horizontal direction along the XY plane is an ellipse, a rectangle, or a polygon with pentagons or more sides, fins whose aspect ratio of the rectangle, or the ratio of the length L in the major axis LG direction of the ellipse or polygon to the length S in the minor axis TG direction (see FIG. 3 described later as an example) is classified as being in the range of 1:1 to 5:1, are understood to be included in the concept of rod-like fins (pin fins). This ratio is also called the aspect ratio, as disclosed in, for example, republished patent WO 2012 / 114955.

[0044] <Basic Configuration> <Cooling (First Rod-Shaped Pins)> The heat sink 12 described above has the following basic configuration. The base plate 20, which functions as a base, has an upper surface 20U (first surface) that abuts against the three semiconductor packages PK1, PK2, and PK3 and allows the semiconductor packages PK1, PK2, and PK3 to be arranged, and a lower surface 20L (second surface) that faces the upper surface 20U and is back-to-back with the upper surface 20U. The cover 14 described above covers the lower surface 20L, leaving a space. This space accommodates rod-shaped fins 22, which will be described later, and functions as a cooling space SP through which a cooling fluid FL, which will be described later, flows while contacting the surfaces of the rod-shaped fins 22.

[0045] On this lower surface 20L, a plurality of cooling areas C1, C2, C3 (see FIG. 3 ) having the same or different heat exchange amounts required for cooling each of the three packages PK1, PK2, PK3 are arranged in a vertical row along the flow direction of the cooling fluid FL (Y-axis direction (predetermined direction), hereinafter sometimes simply referred to as "Y"). These cooling areas C1, C2, C3 are back-to-back and directly opposite the occupied areas of the respective packages PK1, PK2, PK3 arranged on the upper surface 20U of the base plate 20. Of course, depending on the design, each of the plurality of cooling areas C1, C2, C3 may be set larger than the occupied area by a predetermined margin.

[0046] One of the features of this heat sink 12 is that, as shown in Figure 3, three cooling areas C1, C2, and C3 having the same (or different) heat exchange amounts required for cooling are arranged in a vertical row along the flow direction Y of the cooling fluid FL, and that the heat sink 12 is provided with first to third fin assemblies G1, G2, and G3 each consisting of rod-shaped fins 22 (first rod-shaped fins 221) that are erected in each of the cooling areas C1, C2, and C3 and that exhibit cooling capacity according to the heat exchange amount required for each area.

[0047] Each of these first to third fin assemblies G1, G2, G3 has an elliptical cross-sectional shape parallel to the XY plane, and is configured with a plurality of streamlined first rod-shaped fins 22 (221) shaped so that the ratio of the length L in the direction of the major axis LG to the length (thickness) W in the direction of the minor axis SG is within the range of L:W = 5:1, as shown in Figure 4, thereby forming the first to third fin assemblies G1, G2, G3.

[0048] The first distinctive feature of this arrangement is that the longitudinal axis LG of each first rod-shaped fin 221 is aligned with the flow direction Y of the cooling fluid FL (see FIGS. 3 and 4). Therefore, the fluid FL flows along the streamlined side surfaces SF of each first rod-shaped fin 221 (see arrows F11 and F12 in FIG. 4). In other words, depending on the fin design, the area of ​​each fin side surface SF can be made larger than the side surface (part of the circumferential surface) of a typical round bar fin. In other words, if the flow velocity of the fluid FL is the same, the first rod-shaped fin 221 has a larger contact area with the fluid FL than a round bar fin, thereby increasing the heat exchange rate.

[0049] The second feature lies in the fin arrangement of each of the first to third fin assemblies G1, G2, and G3. As can be seen from FIG. 4 , the first rod-shaped fins 221 are arranged in fin columns J1 to Jn (n is a positive integer in this embodiment), each of which includes a plurality of first rod-shaped fins 221 arranged in a vertical column in the flow direction Y (Y-axis direction) with a constant gap GP between them. These fin columns J1 to Jn are arranged in each cooling area C1 (C2, C3) at horizontal positions x1, x2, x3, ..., xn positioned at a constant pitch PT (see FIG. 4 ) in the horizontal direction X (X-axis direction) perpendicular to the flow direction Y (Y-axis direction). That is, each fin column J1 (to Jn) includes a plurality of first rod-shaped fins 221 arranged in a vertical column in the cooling area C1 (C2, C3) with a length L along the major axis LG and a constant gap GP (see FIG. 4 ).

[0050] In addition, as can be seen from Figures 3 and 4, among the multiple fin columns J1 to Jn, the odd-numbered fin columns J1...Jn-1 are composed of an odd number (e.g., seven) of first rod-shaped fins 221, while the even-numbered fin columns J2...Jn are composed of an even number (e.g., six) of first rod-shaped fins 221, which is one less than the odd-numbered fin columns J1...Jn.

[0051] Moreover, in the horizontal direction X, every other fin from the first fin column J1 is connected to the first rod-shaped fin 221 at the top of the column. １ (221 ３ ...) are arranged to protrude upstream in the flow direction Y by a length HF that is approximately half a fin (see FIGS. 3 and 4). As a result, the first rod-shaped fins 221 are arranged in a staggered pattern when viewed both in the lateral direction (X-axis direction) and in the flow direction (Y-axis direction). This staggered fin arrangement is achieved by the first rod-shaped fins 221 that are arranged to protrude in the flow direction Y, as described above. １ , 221 ３ , .... Therefore, the first rod-shaped fin 221 at the front １ , 221 ３ , . . . in the lateral direction X, the cooling fluid can easily flow in (see FIGS. 3 and 4).

[0052] Therefore, the fluid components that flow into this gap CS are directed to the first rod-shaped fins 221 at the head of the even-numbered fin columns J2, J4, . ２ , 221 ４ , ...and are diverted to both sides in the horizontal direction X while heading in each direction. These diverted flow components then become nearly laminar flows and flow along the Y-axis direction between the fin columns J1 to Jn (see arrow F1). In this way, the staggered arrangement of the fin columns J1 to Jn causes the first rod-shaped fin 221 with an elliptical cross section located at the head of the columns to produce a rectifying effect, converting the subsequent flow into a nearly laminar flow.

[0053] As shown in FIG. 4 , this "near-laminar flow" refers to a flow pattern in which the fluid FL flows along a narrow flow path PA formed between the fin columns J1-Jn in the board longitudinal direction Y while contacting and following the streamlined surfaces of each rod-shaped fin 221 (see arrows F11 and F12). This near-laminar flow is schematically represented by the arrows F11 and F12 slightly deflecting in the lateral direction X for each fin. Therefore, unlike when linear flow paths are formed between the fin columns J1-Jn (i.e., when the arrows F11 and F12 flow substantially along the board longitudinal direction Y), the fluid flowing through the flow path PA can flow at a high speed while regularly deflecting slightly left and right (in the lateral direction X).

[0054] Thus, by virtue of the two features, namely, that the first rod-shaped fins 221, each having an elliptical cross section, are arranged in a row along the fluid flow direction Y (Y-axis direction), and that the first rod-shaped fins 221 are arranged in a staggered pattern when viewed from the fluid FL flow direction Y, the area over which the fluid FL comes into contact with the fins can be increased and the flow rate can be increased, thereby enabling a greater amount of heat exchange to be achieved if other design conditions are the same.

[0055] As another feature, let us consider the output side of each of the first to third fin assemblies G1, G2, and G3 in the three cooling areas C1, C2, and C3. For example, focusing on the portion Gout shown in FIG. 3 , similar to the inlet side of the fluid FL, every other fin column J1 to Jn has a configuration in which the first rod-shaped fins 221 protrude downstream by approximately half the length HF of a fin, as described above. This protruding fin configuration also has the effect of urging (pushing) the fluid FL toward the downstream area. This contributes to the creation of the near-laminar flow in the downstream second and third cooling areas C2 and C3. This near-laminar flow of the cooling fluid FL can further reduce pressure loss as the fluid flows sequentially through the three cooling areas C1, C2, and C3.

[0056] The above-described staggered vertical arrangement of the fins and the arrangement of every other leading fin of the fin columns J1 to Jn protruding in the flow direction Y are the same in the multiple cooling areas C1, C2, and C3. Of course, if the required heat exchange amount differs for each cooling area, factors such as the size, number, and arrangement density of the first rod-shaped fins 221 can be changed as appropriate while maintaining the above-described basic fin arrangement.

[0057] Additionally, in the above-described configuration, the three cooling areas C1, C2, and C3 are separated from one another in the flow direction (predetermined direction) Y of the cooling fluid FL. Specifically, as can be seen from Fig. 3, first and second separation areas S1 and S2 are set on the lower surface 20L of the base plate 20, which spatially separate two cooling areas C1 and C2 (C2 and C3) that are adjacent to each other in the flow direction Y among the three cooling areas C1, C2, and C3 by a distance Yx.

[0058] Alternatively, the three cooling areas C1, C2, and C3 may be arranged adjacent to each other with only a small gap of a predetermined width provided so that they are substantially adjacent to each other in the flow direction Y, without providing the separation areas S1 and S2.

[0059] In addition to the first and second separation areas S1 and S2 described above, an inlet area IT is provided which is connected to the input port 16A and allows the cooling fluid to flow in upstream in the flow direction Y, and an outlet area ET is provided which is connected to the output port 16B and allows the cooling fluid to flow out downstream in the flow direction Y.

[0060] Alternatively, the inlet area IT may be omitted so that the input port 16A is directly connected to the first-stage cooling area C1.

[0061] The flow direction Y (predetermined direction) is a linear direction from the entrance area IT to the exit area ET, and the entrance area IT and the exit area ET are formed on the lower surface 20L of the base plate 20 so as to face each other in the flow direction Y. In this embodiment, the input port 16A and the output port 16B described above are also similarly faced each other in the flow direction Y.

[0062] In this embodiment, no rod-shaped fins are provided in the two separation areas S1 and S2, the inlet area IT, and the outlet area ET. That is, in these separation areas S1 and S2, the inlet area IT, and the outlet area ET, the cooling fluid FL flows along the area (i.e., the lower surface 20L) without resistance due to the fins.

[0063] <Flow Control (Second Rod Fin)> Furthermore, a characteristic configuration of the rod fin heat sink according to the present disclosure will be described.

[0064] The lower surface 20L of the base plate 20, that is, the region in the cooling space SP, cooperates with the rod-shaped fins 22 to exchange heat with the fluid FL. Therefore, although it is desired that heat exchange occur in the cooling areas C1, C2, and C3, in reality, the continuous base plate 20 (metal plate) cannot distribute the transferred heat to only localized regions. Therefore, the fluid FL also passes through the peripheries of the cooling areas C1, C2, and C3, thereby promoting the heat exchange action.

[0065] Furthermore, from the viewpoint of controlling the flow of the cooling fluid FL, as shown in Fig. 3, side areas ER and EL having a constant width Xf are set along the longitudinal direction (Y-axis direction: fluid flow direction) on both sides of the cooling areas C1, C2, and C3, the separation areas S1 and S2, the entrance area IT, and the exit area ET in the lateral direction (X-axis direction) of the base plate 20. Of course, it is also possible to provide only one of the side areas ER and EL. Furthermore, the widths of the side areas ER and EL in the lateral direction (X-axis direction) may be different from each other.

[0066] According to this configuration, as shown in Fig. 3, a plurality of rod-shaped fins 22 (second rod-shaped fins 222) having a rectangular cross section are arranged in both the side areas ER and EL. These rod-shaped fins 22 have a rectangular cross section (XY cross section) perpendicular to the height direction LE (Z-axis direction), but are configured as so-called plate-shaped fins. These plate-shaped fins are also formed so that the aspect ratio of the cross section described above falls within the range that allows them to be regarded as rod-shaped.

[0067] The plurality of rod-shaped fins 22 (second rod-shaped fins 222) therefore have flat side surfaces SD, but are arranged so that the side surfaces SD are angled at a constant angle θ with respect to the flow direction Y (sink longitudinal direction). This angled arrangement is the same in both side areas ER and EL. Furthermore, in each of the side areas ER and EL, the angled arrangement density of the fins in the flow direction Y is constant, as can be seen from FIG. 3 .

[0068] Therefore, the second rod-shaped fins 222 in each of the side areas ER and EL function, via their side surfaces SD, to bias (push) the cooling fluid FL flowing in from the input port IT from both sides toward the center in the short direction X. This biasing exerts a control function of directing the flow of the fluid FL toward the center (see arrows OQ in FIG. 3 ). Despite this biasing action, gaps are formed between the second rod-shaped fins 222, and therefore some fluid components (not shown) pass through (seep out of) the gaps. These fluid components provide supplemental cooling capacity by heat exchange via the second rod-shaped fins 222 in each of the side areas ER and EL.

[0069] Therefore, the flow control function of the second rod-shaped fins 222 concentrates the inflowing cooling fluid FL in the central region in the horizontal direction (X-axis direction), i.e., toward the cooling areas C1, C2, and C3. A portion of the fluid FL is also used to perform auxiliary heat exchange in the side areas ER and EL, contributing to cooling. In this way, the side areas ER and EL maintain auxiliary cooling capacity, thereby assisting the cooling areas C1, C2, and C3 in achieving their desired cooling capacity. By concentrating as much cooling capacity as possible in the cooling areas C1, C2, and C3, the cooling areas C1, C2, and C3 can provide their desired cooling capacity more quickly (i.e., with a shorter time constant until thermal equilibrium). As a result, cooling energy can be efficiently concentrated in the areas requiring it. Additionally, the flow of the cooling fluid FL, which is close to a rectified laminar flow in each of the cooling areas C1, C2, and C3, reduces flow pressure loss. These advantages result in energy savings for the entire heat sink.

[0070] As a modified example, the arrangement density of the second rod-shaped fins 222 may be formed to decrease continuously or in steps toward the downstream side in the sink longitudinal direction Y (flow direction). The reason for this is that, toward the downstream side, the degree of convergence of the fluid toward the output port 16B increases, and the flow control function may become weaker.

[0071] <Overall Operation> Therefore, the cooling fluid FL discharged from the fluid source 19 flows into the cooling space SP from the input port 16A and flows through the cooling space SP in the sink longitudinal direction Y according to the thermal resistance of the entire fluid system. As a result, the fluid FL passes in order from the rod-shaped fin (pin fin) assembly G1 located on the most upstream side to the rod-shaped fin (pin fin) assembly G3 located on the most downstream side, exits from the output port 16B, and returns to the fluid source 19. The circulation of the fluid FL is continuous throughout the heat sink 12 as a whole, at a flow rate and flow rate according to the discharge pressure P (i.e., flow rate (m / s)) of the fluid source 19 and the thermal resistance K (°C / W) of the fluid system of the heat sink 12, as schematically shown in Figure 5.

[0072] During this fluid passage, the fluid passes between the fin assemblies G1 arranged in the most upstream cooling area C1 and comes into contact with the surfaces of the first rod-shaped fins 221 (see arrow F1). As a result, heat generated from the semiconductor package PK1 located in the first cooling area C1 is transferred through the base plate 20 to each of the first rod-shaped fins 221, and the heat is exchanged by contact with the fluid FL (heat exchange amount QS1) and absorbed by the fluid FL. The fluid FL, whose temperature has risen due to this heat absorption, is designed to still have a margin for heat exchange (see FIG. 6).

[0073] In this embodiment, the first rod-shaped fins 221 have an elliptical cross section and their major axes LG are oriented along the flow direction Y of the cooling fluid FL, as shown in Figures 3 and 4. Furthermore, the first rod-shaped fins 221 are arranged in a vertical row along the flow direction Y (Y-axis direction). Therefore, the flow F1 between every other vertical row of the first rod-shaped fins 221 in the short direction X has less resistance than the flow between rows of similarly arranged round-rod fins, resulting in a faster flow and a flow that is closer to laminar flow. Furthermore, the surface area R of each first rod-shaped fin 221 in the flow direction Y is larger than that of, for example, a round-rod fin. In other words, the multiple vertical rows J1 of the first rod-shaped fins 221 offer less resistance to the fluid FL and can increase the contact surface area R. In other words, the fluid FL flows at a higher speed while making greater contact with each fin 221.

[0074] Furthermore, as can be seen from FIG. 3, the arrangement of the plurality of first rod-shaped fins 221 in the short-side direction X, i.e., the arrangement of the plurality of columns J1, is such that the leading first rod-shaped fins 221 are positioned in a staggered manner. １ , 221 ２ , ... are staggered in the flow direction Y. Therefore, the leading first rod-shaped fins 221 １ , 221 ２ , . . . can provide a flow straightening effect between the adjacent two adjacent ones of the plurality of nozzles to guide the fluid flow to a flow close to laminar flow.

[0075] Furthermore, in this embodiment, no rod-shaped pins of any type are arranged in the exit area ET.

[0076] As a result, the flow of the cooling fluid FL in the first fin assembly G1 can be more reliably converted into a flow that is closer to laminar flow, and the pressure loss of the flow is also reduced, so that the high-speed flow F1 allows for more heat exchange and provides efficient cooling capacity.

[0077] After the first stage of cooling is completed as described above, the fluid FL passes through the fin assembly G2 located in the next stage (see arrow F2). During this process, the fluid FL comes into contact with the surfaces of the rod-shaped fins 22, thereby cooling the cooling area C2, i.e., the semiconductor package PK2, through the same heat exchange (heat exchange amount QS2) as described above. The cooling capacity (heat exchange amount) of the fluid after this cooling process is set to still have a certain amount of reserve (see FIG. 6). Therefore, the cooling fluid FL then passes through the fin assembly G3 located in the final stage (see arrow F3). During this process, the fluid FL comes into contact with the rod-shaped fins 22, thereby cooling the cooling area C3, i.e., the semiconductor package PK3, through the same heat exchange (heat exchange amount QS3) as described above (see FIG. 6). Of course, the cooling fluid FL passing through the second and third fin assemblies G2 and G3 that line up in these cooling areas C2 and C3 can also obtain the more efficient cooling capacity enjoyed by the first fin assembly G1 that lines up in the first-stage cooling area C1 described above.

[0078] In this way, the multiple cooling areas C1, C2, C3 are arranged in a vertical row along the flow direction Y (sink longitudinal direction) of the cooling fluid FL discharged from a single fluid source. In other words, multiple packages PK1, PK2, PK3 having the same (or different) heat exchange amounts QS1, QS2, QS3 required for cooling can be arranged in a vertical row on the upper surface 20U of the base plate 20. For example, in the case of a three-phase AC inverter, the three semiconductor packages PK1, PK2, PK3 package switching semiconductors for the U, V, and W phases, and typically, the cooling capacities required for the U, V, and W phases are the same for these semiconductor packages PK1, PK2, PK3.

[0079] Furthermore, in the case of equipment requiring a set of three semiconductor packages PK1, PK2, and PK3, the first semiconductor package PK1 is used for controlling a three-phase inverter of a motor, and the second and third semiconductor packages PK2 and PK3 are used for a DC-DC converter, a DC-AC converter, etc. In such cases, the cooling capacities required for the semiconductor packages PK1, PK2, and PK3 often differ from one another.

[0080] As described above, two types of rod-shaped fins 221, 222 with different cross sections in the lateral direction (direction along the XY plane) are arranged in the target cooling areas C1, C2, C3 and their side areas FL, FR on the underside 20L of the base plate 20 facing the cooling space SP. This allows the entire underside 20L of the base plate 20 to exert a cooling effect, which facilitates cooling that meets the required values ​​for the cooling areas C1, C2, C3.

[0081] In addition, design factors such as the type of rod-shaped fins arranged in each area (e.g., round rods with a circular cross section, elliptical rods with a streamlined cross section, plate fins with a rectangular cross section, etc.), their cross-sectional size, height, and arrangement density can be appropriately changed. This allows the cooling areas C1, C2, and C3 to be arranged in order from the upstream side toward the downstream side according to the cooling demand. As a result, as schematically shown in FIG. 6 , the cooling energy of the cooling fluid discharged from one fluid supply device 19 can be consumed in each cooling area, starting with the first cooling area C1, while simultaneously (parallel) cooling three semiconductor packages PK1, PK2, and K3 with heat exchange rates QS1, QS2, and QS3 according to the cooling demand.

[0082] In particular, unlike conventional heat sinks of this type, this embodiment can exert control over the flow direction of the fluid FL, which is achieved by obliquely arranging the second rod-shaped fins 222 with rectangular cross sections, as described above. This allows cooling energy to be more concentrated in the cooling areas C1, C2, and C3 that require cooling, thereby improving the cooling efficiency of the entire heat sink.

[0083] Of course, the cross section of the second rod-shaped fins 222 does not necessarily have to be rectangular or circular. For example, a rod-shaped fin having a diamond or triangular cross section may be used as long as it can provide similar control and function. Furthermore, the second rod-shaped fins 222 may be arranged obliquely to control the flow direction of the second rod-shaped fins 222. As mentioned above, the shape of the rod-shaped fins (also called pin fins) arranged in each cooling area may be, for example, a round, diamond, elliptical, triangular, or more polygonal cross section intersecting the fin height direction. Therefore, the heat exchange capacity is appropriately set based on design factors such as the cross-sectional shape, size, height, and pin arrangement density to suit the required heat exchange capacity.

[0084] In this embodiment, the above-described flow direction control can be achieved, and a high-speed fluid flow close to laminar flow can be obtained. Therefore, in addition to the simple cooling structure using a single fluid circulation means for the vertically arranged semiconductor packages described above, the transition to a thermal equilibrium state can be more rapid, the pressure loss of the flow can be reduced, and the overall cooling energy can be reduced. Therefore, for the same cooling conditions, the capacity required for the fluid supply device 19 can be smaller, allowing for the overall system to be made more compact.

[0085] Furthermore, the flow direction Y (sink longitudinal direction) of the fluid FL is linear, and the inlet area IT and the outlet area ET face each other along the flow direction Y. This allows the areas and pin arrangement to be designed symmetrically in the horizontal direction (X-axis direction) perpendicular to the flow direction Y, which has the advantage of simplifying the design. [Second Embodiment] Furthermore, a rod fin heat sink according to a second embodiment of the present disclosure will be described with reference to FIG.

[0086] In this embodiment and subsequent embodiments and variants, components that perform the same or equivalent functions as those described in the first embodiment will be given the same symbols, and their descriptions will be omitted or simplified.

[0087] Fig. 7 shows a schematic diagram of an example of the arrangement of the rod-shaped fins 22 of the rod-fin heat sink 12A according to the second embodiment, which is shown in the same plan view as Fig. 3 described in the first embodiment.

[0088] This rod-shaped fin heat sink 12A differs from that described in the first embodiment in the fin arrangement for enhancing the above-mentioned rectifying effect, but the rest of the configuration is the same as that of the first embodiment.

[0089] For this purpose, as shown in FIG. 7, the inlet area IT and the first and second separation areas S1 and S2 are each provided with a guide fin row B ３ ~B ｎ－１ In this embodiment, no guide fin row is arranged in the exit area ET. In other words, this guide fin row is arranged only in the empty area before the cooling areas C1, C2, and C3.

[0090] Specifically, as shown in FIG. 6, in each of the first, second, and third fin assemblies G1, G2, and G3, the row positions in the horizontal direction (X-axis direction) of the plurality of fin columns J1, J2, ... arranged in the flow direction Y (Y-axis direction) are defined as x １ , x ２ , x ３ , …x ｎ Each of the multiple fin columns J1, J2, ... has multiple first rod-shaped fins 221 arranged in a column along the flow direction Y with a predetermined gap between them. This arrangement itself is the same as the arrangement described in the first embodiment.

[0091] In addition, the third row position P ３ The "n-1th" row position P every other row ｎ－１ In each of the third fin columns J ３ , J ５ , …J ｎ－１ On the upstream side of the guide fin row B ３ , B ５ , …B ｎ－１ are arranged respectively.

[0092] These guide fin rows B ３ , B ５, …B ｎ－１ are arranged in pairs along the flow direction Y. Each of the third rod-shaped fins 22 (223) has a circular cross section in the horizontal direction (XY plane direction). １ , 223 ２ ) are arranged with a predetermined gap. １ , 223 ２ ) diameter r ａ is formed to be equal to or smaller than the length S of the first rod-shaped fin 221 in the direction of the minor axis TG (r a ≦S).

[0093] In addition, each guide fin row B ３ (B ５ , ...) may be configured by a vertical arrangement of three or more rod-shaped fins with a circular cross section spaced apart from each other, or may be rod-shaped fins with an elliptical cross section, a rhombic cross section, or even a triangular cross section. ３ (B ５ , ...) may be composed of a single rod-shaped fin, in which case it is more convenient to use an elongated rod-shaped fin with an elliptical cross section.

[0094] In this embodiment, in order to control the flow direction, the fin assemblies formed by the oblique arrangement of the second rod-shaped fins 222 are arranged in rows in both side areas EL and ER. １ , P ｎ A guide fin row may also be arranged on the

[0095] In this manner, in this embodiment, the guide fin row B ３ , B ５ , …B ｎ－１ are arranged upstream of the cooling areas C1, C2, and C3 in the flow direction Y. This strengthens the rectification of the flow of the fluid FL toward the fins in row positions P2, P4, ... before it flows into the first, second, and third fin assemblies G1, G2, and G3, respectively. Therefore, the flow of the fluid FL passing between the fin columns in the first, second, and third fin assemblies G1, G2, and G3 also becomes closer to a laminar flow, increasing the amount of heat exchange and providing more efficient cooling capacity.

[0096] Other effects and advantages are the same as those obtained in the first embodiment.

[0097] <Modification 1> A modification of the rod-fin heat sink according to the second embodiment will be described with reference to FIG.

[0098] In the rod-shaped fin type heat sink 12B according to this modification, the guide fin row B described in the second embodiment is ３ , B ５ , …B ｎ－１ Specifically, as shown in FIG. 7, the row position in the horizontal direction (X-axis direction) is set to x ３ , x ５ , …x ｎ－１ The third fin column J is disposed ３ , J ５ , …J ｎ－１ Each leading rod-shaped fin 221 ｈ The oval cross section of the first fin 221 is made thinner and more elongated. ｈ In terms of the manufacturing process, it is desirable that the ratio of the length R' in the long axis direction LG to the length S in the short axis direction TG is within the range of a rod-shaped fin (pin fin), for example, 5:1. ｈ The length R' of the elongated rod-shaped fin 221 has a relationship of R'>R with respect to the length R of the other rod-shaped fins 221. ｈ The structure of is adopted in each of the first, second and third fin assemblies G1, G2 and G3.

[0099] Therefore, the elongated rod-shaped fin 221 ｈ is the aforementioned guide fin row B ３ , B ５ , …B ｎ－１ Similarly, the flowing cooling fluid FL flows through the adjacent rod-shaped fins 221 ｈ The gaps between the leading ends of the two pipes cause the flow to be diverted further upstream, thereby achieving the aforementioned flow straightening effect.

[0100] The structure and effects other than those described above are the same as those of the second embodiment. The structure is simpler because it only requires extending some of the rod-shaped fins located at the leading ends of the first, second, and third fin assemblies G1, G2, and G3.

[0101] <Modification 2> Next, a description will be given of Modification 2. Modification 2 relates to a modification of the rod-shaped fin heat sink according to the second embodiment described above.

[0102] Fig. 9 shows a schematic diagram of an example of the arrangement of the rod-shaped fins 22 of the rod-fin heat sink 12C according to Modification 2. Fig. 9 shows the same arrangement example as Fig. 7 described in the second embodiment in plan view.

[0103] In this rod-fin heat sink 12C, the rod-shaped fins arranged in each (or one) of the side areas ER and EL are rod-shaped fins 22 (223) with a circular cross section in the horizontal direction. These round rod-shaped fins 223 are arranged in place of the rod-shaped fins 22 (222) with a rectangular cross section described above, and, as described above, perform the flow control function of biasing the flow of the fluid FL toward the cooling areas C1, C2, and C3.

[0104] As shown in the figure, the arrangement density of the round bar-shaped fins 223 is set to decrease as one moves downstream, because the flow of the fluid FL converges more strongly toward the outlet area ET (output port 16B) as one moves downstream.

[0105] Furthermore, in this modification, there are three cooling areas, namely, first to third cooling areas C1 to C3. However, the cooling capacities of the first fin assembly G1 erected in the first cooling area C1 and the second and third fin assemblies G2 and G3 erected in the second and third cooling areas C2 and C3 are set such that QS1 > QS2, QS3 (or QS2 = QS3). This is set by changing the size and arrangement density (number) of the first rod-shaped fins 221, which have an elliptical cross section. The heights of the fins may be different from each other.

[0106] Therefore, this modification can also achieve the same effects as those of the second embodiment. The round bar-shaped fins 223 have a relatively large contact area with the fluid FL and ensure a moderate flow rate, making them suitable for filling areas other than the cooling area.

[0107] Of course, in the second and third fin assemblies G2 and G3 erected in the second and third cooling areas C2 and C3, the cooling capacity can be set to QS2 > QS3 (or QS2 < QS3) by making factors such as the size, arrangement density (number of arrangements), and height of the first rod-shaped fins 221 different from each other.

[0108] Although not shown, a combination of fins with a round bar cross section and fins with a rectangular cross section may be arranged in either or both of the side areas ER and EL.Furthermore, fins of either shape may be additionally arranged in the exit area ET.

[0109] 10, a rod-shaped fin heat sink 12D according to another modification may have two cooling areas C1 and C2, i.e., two semiconductor packages PK1 and PK2 to be cooled. In this case, the cooling capacities QS1 and QS2 of the first and second cooling areas C1 and C2 located upstream and downstream are set such that QS1 > QS2 or QS1 = QS2.

[0110] In this modified example 3, one or more of the configurations described in the first embodiment, the second embodiment, modified example 1, and modified example 2 can also be combined and implemented.

[0111] Of course, the number of semiconductor packages to be cooled that can be implemented in the vertical arrangement structure of semiconductor packages according to the present disclosure may be three as described above, or may be four or more.

[0112] <Modification 4> A rod-fin heat sink according to Modification 4 will be described with reference to FIG.

[0113] A rod-shaped fin heat sink 12E according to this embodiment is shown in FIGS. 11(A), 11(B), and 11(C) as schematic side, top, and bottom views, respectively.

[0114] The basic configuration of this rod-fin heat sink 12E is different from the heat sink 12A using the base plate 20 and rod-shaped pins 22 described in the second embodiment, particularly in the arrangement of the rod-shaped pins erected in the entrance area IT and the separation areas S1 and S2, and the arrangement density of the rod-shaped pins arranged in both side areas EL and ER. The rest of the structure is the same as that of the second embodiment.

[0115] In the cooling areas C1 to C3, rod-shaped fins 22A, 22B, and 22C having an elliptical cross section for cooling are arranged with the size and arrangement density adjusted so that the cooling capacities QS1, QS2, and QS3 are different from one another. Furthermore, in the left and right side areas EL and ER, rod-shaped fins 22D having a rectangular cross section similar to the above-mentioned rectangular rod-shaped fins 22 are erected so that the arrangement density decreases toward the downstream in the flow direction Y.

[0116] 11A and 11C, rod-shaped fins 22D (22) are also arranged in the entrance area IT and the separation areas S1 and S2, which are located before and after the flow direction Y (predetermined direction) of the three cooling areas C1, C2, and C3, which are the areas directly targeted for cooling. These rod-shaped fins 22D are round rod-shaped fins. Rod-shaped fins may also be arranged in the exit area ET.

[0117] These rod-shaped fins 22D have a relatively large contact area with the fluid FL and are arranged to ensure a moderate flow rate and fluid residence time. In other words, unlike the active flow straightening function described above, the flow rate of the cooling fluid can be appropriately adjusted. For example, in the inlet area IT, the flow rate of the cooling fluid FL is reduced, lengthening the time it takes for the cooling fluid FL to pass through the bar-shaped fins 22D that line the inlet area IT. At the same time, in a steady flow state, the flow of the fluid FL from the inlet area IT into the first-stage cooling area C1 is urged. This urging inflow is also accelerated by the fact that the rod-shaped fins 22A (22B, 22C) arranged in the cooling area C1 are elliptical rod-shaped fins with their major axes LG aligned along the fluid flow direction Y. The same applies to each separation area S1, S2.

[0118] The arrangement density and arrangement positions of the rod-shaped fins 22D are adjusted so as not to generate turbulence in each area.

[0119] In this embodiment, if the cooling capacity required by the first semiconductor package PK1 (i.e., the cooling capacity to be exerted by the first fin assembly G1) is QS1 and the cooling capacities required by the second and third semiconductor packages PK2 and PK3 (i.e., the cooling capacities to be exerted by the second and third fin assemblies G2 and G3) are GL2 and QS3, respectively, then the relationship "QS1 > QS2, QS3" and "QS2 ≥ QS3" are maintained. The design defines the magnitude relationship between the fluid discharge capacity of the fluid supply device 18 and the cooling capacities exhibited by the assemblies G1, G2, and G3 of the base plate 20 and rod-like fins (pin fins) 22.

[0120] Therefore, the heat sink 12E allows for the use of a cascade cooling fluid (water, air, refrigerant) supplied from a single fluid supply device 18. The semiconductor package PK1, which requires the highest cooling capacity, is cooled first at an upstream position, and the semiconductor packages PK2 and PK3, which require lower cooling capacity, are then cooled downstream by the cooled semiconductor package PK1. This allows for sequential cooling of the multiple semiconductor packages PK1, PK2, and PK3 along the flow direction Y. In this case, the round-bar fins 22D provide appropriate flow suppression and cooling functions, making it easy to accommodate diverse design conditions and allowing each of the multiple cooling areas arranged in a vertical row to exhibit an appropriate cooling capacity.

[0121] As a result, even when multiple (types) of semiconductor packages PK1, PK2, and PK3 require different cooling capacities, improved energy efficiency can be expected compared to cooling using individual heat sinks. Furthermore, by arranging the multiple (types) of semiconductor packages PK1, PK2, and PK3 on a single base plate 20 and using a single cooling source, the entire cooling device system can be made more compact. Naturally, the multiple (types) of semiconductor packages PK1, PK2, and PK3 can be arranged together in a single location closer to the target device (such as a motor), which is convenient in terms of mounting.

[0122] <Modification 5> A heat sink 112F according to a fourth embodiment shown in Fig. 12 is a heat sink in which the pin arrangement shown schematically in Fig. 11(C) is formed in more detail. Note that components that have the same or equivalent functions as the components described above are given the same reference numerals, and descriptions thereof will be omitted or simplified.

[0123] Similar to the basic configuration and modifications described above, this heat sink 112F has an inlet area IT and an outlet area ET to which an input port and an output port are connected, respectively, and a linear flow path is formed between these two areas IT and ET, with a first cooling area C1, a first separation area S1, a second cooling area C2, a second separation area S2, and a third cooling area C3 set in this flow path from the upstream side. The functions of each area are the same as those described in Modification 4. Furthermore, side areas ER and EL for fluid biasing, as described in the modifications described above, are formed on both sides in the lateral direction X perpendicular to the flow direction Y.

[0124] In each of the first to third cooling areas C1 to C3, multiple rod-shaped fins 22 (22C) with elliptical cross sections perpendicular to the longitudinal direction LE are arranged in a staggered pattern. Furthermore, multiple rod-shaped fins 22D with round cross sections are arranged in the entrance area IT and the first and second separation areas S1 and S2. Multiple rod-shaped fins (plate-shaped pins) 22E with flat sides are arranged in the side areas ER and EL at a predetermined angle θ in the flow direction Y with uniform density.

[0125] As an example, the rod-shaped fins 22D (circular in cross section) arranged in the inlet area IT and the first and second separation areas S1 and S2 have a diameter of 1.8 mm, the rod-shaped fins 22A with an elliptical cross section arranged in the first cooling area C1 have a length of 4 mm in the major axis direction and a length of 1.2 mm in the minor axis direction, and the rod-shaped fins 22B and 22C with an elliptical cross section arranged in the second and third cooling areas C2 and C3 have a length of 3 mm in the major axis direction and a length of 1.2 mm in the minor axis direction. Furthermore, the rod-shaped fins 22E with a rectangular cross section arranged in the fluid energizing areas ER and EL on both sides have a size of 2 mm x 1.2 mm. The height of each rod-shaped fin is selected appropriately between approximately 3 mm and 5 cm.

[0126] Such a forest of fine pins is manufactured by, for example, brazing or diffusion bonding the bottom surface of the base of each pin 22 to the lower surface 20L of the base plate 20.

[0127] This fine pin arrangement structure provides the same effects as those described in the fourth modification.

[0128] <Variation 6> Variation 6 also relates to a configuration applicable to all of the basic configurations and variations thereof according to the above-described embodiments, and relates to the shape in the height direction (Z-axis direction) of the rod-shaped fins erected in all areas C1, C2, C3, S1, S2, IT, ET, and ER, EL, or some of the areas C1, C2, C3.

[0129] 13A and 13B are schematic diagrams of cross sections taken along the cross section CC' line (FIG. 13A) and the cross section DD' line (FIG. 13B) in FIG. 7. As can be seen from these diagrams, the side shapes of the plurality of third rod-shaped fins 223 arranged in the inlet area IT, when viewed along the flow direction Y of the fluid FL, are such that, in the upright state of the fins, the inclination angle (negative draft gradient) α from the upper end to the vertical direction is Ａ , α Ｂ (α Ａ >α Ｂ 13A ), the fins 223 are formed so that the horizontal cross-sectional shape gradually increases toward the tip in the fin longitudinal direction LE. That is, as the fin surface area increases and the distance between the fins 223 decreases toward the tip in the longitudinal direction LE, the distance Dr between the fins 223 at their base portions 22R (portions close to the lower surface 20L) is greater than the distance Dt between the fins 223 at their tip portions 22T (Dr>Dt).

[0130] This shape feature (α Ａ >α Ｂ ) is also the same for the first rod-shaped fin 22 (221) (see FIG. 13(B)).

[0131] As a result, the flow resistance of the fluid FL at the base of the fin is smaller than that at the tip of the fin. Therefore, the spatial region along the lower surface 20L of the base plate 20 exhibits a relatively smaller flow resistance than the region at the tip. As a result, more fluid FL flows in the portion along the lower surface 20L, and more heat is absorbed from the lower surface 20L, thereby enhancing the heat absorption effect.

[0132] This substantially inverted triangular structure with the inclination angle α can be applied to all or part of the separation areas S1 and S2.

[0133] The above-mentioned inclination angle (draft gradient) α Ａ , α Ｂ α is set so that the rod-shaped fins stand upright in the upright fin state without adding Ａ = α Ｂ = 0, and Dr = Dt.

[0134] <Modification 7> An outline of Modification 7 is shown in FIGS. 14(A) and 14(B).

[0135] In the above-described embodiments and their modified examples, the flow direction Y of the cooling fluid FL is linear in the base plate 20. That is, the inlet area IT and the outlet area ET are directly opposite each other in the Y-axis direction, but the present invention is not necessarily limited to such an arrangement.

[0136] For example, in the rod-shaped fin type heat sink 112G shown in FIG. 14A, the cooling fluid FL flowing in from the inlet area IT connected to the input port 16A flows in the direction indicated by the arrow YJ. １ As shown in Fig. 1, the air changes direction in a crank shape at the inlet area IT, passes through two predetermined cooling areas Cm, Cn and a separation area Sm, and then flows out from the output port 16B via the outlet area ET. That is, the input port 16A and the output port 16B are positioned offset from each other in the short-side direction X of the board.

[0137] In the cooling areas Cm, Cn, and separation area Sm, rod-shaped fins are erected in each area, forming a fin assembly, as described above. The entrance area IT and exit area ET each include a direction-changing area Acon1, Acon2, in which the plate fins (rod-shaped fins) described above are arranged diagonally, for example, at angles between 0 and 90 degrees. As a specific example, a direction-changing flow path Parc is formed by arranging fins whose angles gradually change between 0 and 45 degrees, as shown in Figure 15 (Variant 8), which will be described later.

[0138] 14B, in the rod-shaped fin heat sink 112H, the input port 16A and the output port 16B are provided at positions shifted from each other in the horizontal direction (X-axis direction), unlike in FIG. 14A, and the flow path of the fluid FL may be cranked in the horizontal direction (arrow YJ). ２ (See section 1.1.2 ...2.1.1.2.1.1.2.1.1.2

[0139] By providing a heat sink in which the arrangement of the input port 16A and the output port 16B is changed in this way, it is possible to increase the degree of freedom in selecting the arrangement direction during mounting.

[0140] 15 illustrates an example of a fin arrangement that can be applied to the direction change area Acon1 shown in part of the inlet area IT shown in FIG. 14B. In a heat sink 112I according to this modification, the inlet area IT is located at the end of the longitudinal direction (Y-axis direction) of the base plate 20, and the fluid inflow and outflow directions are bent by 90 degrees relative to the outlet area ET, as shown in FIG. 15. Therefore, rod-shaped fins 22G with an elliptical cross section are arranged in the direction change area Acon located on the far side of the inlet area IT in the fluid inflow direction, at an angle γ with respect to the flow direction Y (the board longitudinal direction).

[0141] Specifically, in each of two tiers in the horizontal direction (X-axis direction) located behind the entrance area IT, rod-shaped fins 22G are arranged diagonally at an angle of γ = 45°, and the fin rows are arranged along the board longitudinal direction Y. Furthermore, in each of two tiers located behind them, rod-shaped fins 22G are arranged diagonally at an angle of γ = 30°, and the fin rows are arranged along the board longitudinal direction Y. Similarly, in each of two tiers located behind them, rod-shaped fins 22G are arranged diagonally at an angle of γ = 15°, and the fin rows are arranged along the board longitudinal direction Y. In the final tier, rod-shaped fins 22G are arranged at an angle of γ = 0°, i.e., vertically arranged along the board longitudinal direction Y.

[0142] That is, the cooling fluid FL that flows into the inlet area IT then flows along the multiple direction-changing channels Parc formed in the direction-changing area Acon, and sequentially comes into contact with the rod-shaped fins 22G, whose oblique angle γ gradually changes from a deep angle (45°) to a shallow angle (0°). As a result, the inflow direction is gradually bent by 90°, and the fluid FL passes through the flow-straightening rod-shaped fins 22H and flows into the first cooling area C1. Therefore, the fluid FL exchanges heat through the fin assembly G1 provided in the cooling area C1. The fluid FL then passes through another flow-straightening rod-shaped fin 22I and passes through the fin assembly G2 of the next cooling area C2, where it exchanges heat.

[0143] In this way, even if the positional relationship between the inlet area IT and the outlet area ET (i.e., the input port and the output port) is orthogonal, the fluid FT can be reliably changed in direction.

[0144] Further back in this turning area Acon is the rear area A. ＢＫ is formed, and this rear area A ＢＫ A plurality of rod-shaped fins 22H having a rectangular cross section, which do not require heat exchange and are used to cool the base plate 20, are arranged on the base plate 20.

[0145] Even with this structure in which the flow path of the fluid FL is bent 90 degrees, it is possible to cool, for example, two types of semiconductor packages PK1 and PK2 using a single flow of fluid FL in multiple cooling areas C1 and C2. In this case, since the first-stage semiconductor package PK1 can be cooled while the cooling capacity is high, higher cooling capacity can be imparted to the first-stage semiconductor package PK1 even if the packages are the same type, size, shape, and arrangement density. Of course, the cooling capacity for the next-stage semiconductor package PK2 may be adjusted by taking into account design factors such as reducing the pin size (cross-sectional area).

[0146] The structure of the oblique arrangement of the rod-shaped fins 22G arranged in the direction change area Acon can be applied to the direction change area Acon2 on the output port side shown in Fig. 14(B) and can also be applied to the direction change areas Acon1 and Acon2 on the input and output port sides shown in Fig. 14(A).

[0147] 15, rows of rod-shaped fins 22G (with different fin angles depending on the row) are arranged along the longitudinal direction Y of the board, but the angle of a line that virtually passes through the entire row itself may be set at a constant angle with respect to the longitudinal direction Y of the board. In other words, the more downstream each row is in the longitudinal direction Y of the board, the closer it can be positioned to the back in the short direction X of the board. This allows for a variety of designs for the arrangement of fins to change the flow direction of the fluid FL.

[0148] <Modification 9> As shown in FIG. 16, Modification 8 shows another example of a fin arrangement that can be implemented or deployed in each of the direction change areas Acon1 and Acon2 shown in FIGS. 14(A) and 14(B), respectively.

[0149] As shown in FIG. 16 , in the heat sink 112J according to this modification, multiple imaginary arch-shaped trajectories ARC are defined in the direction change area Acon along which the fluid FL is desired to change direction by 90 degrees, i.e., from the board short-side direction X to the board long-side direction Y. Multiple rod-shaped fins 22J with elliptical cross sections are erected along each trajectory ARC at regular intervals. That is, the fluid FL that flows into the inlet area IT then flows into the multiple arch-shaped direction change channels Parc. As a result, the fluid FL is subjected to a rectifying effect and smoothly changes direction by 90 degrees, passing through the rectifying fins 22H and entering the cooling area C1.

[0150] Therefore, in the case of the ninth modification, the same effects as those explained in the eighth modification are obtained.

[0151] The multiple arch-shaped trajectories ARC may be set to describe virtual concentric arcs, which makes the arch-shaped direction-changing flow paths Parc also concentric, making it possible to more smoothly change the direction of the fluid FL and more reliably suppress pressure loss associated with the flow.

[0152] [Third Embodiment] The third embodiment relates to a method for manufacturing a rod-fin heat sink according to the above-mentioned embodiments and their modified examples. This will be explained with reference to Figures 17 to 19, focusing only on the rod-fins 22, their assembly FIN, and the base plate 20 that supports them, and will be described schematically as a heat sink body 30 (see Figure 19(D)). Figure 17 shows an outline of the manufacturing procedure. The rod-fin heat sink to which this manufacturing method is applied is the heat sink described in the various embodiments and their modified examples described above.

[0153] 18(A) to 18(D), a plurality of aluminum or copper rod-shaped fins 22, an aluminum or copper base plate 20 which is a separate part from the rod-shaped fins 22, a carbon pin alignment jig 40, and a pair of plate-shaped carbon clamping jigs 50 are prepared (FIG. 17, step S101). Note that the rod-shaped fins 22 here represent the plurality of types of rod-shaped fins having the various cross-sectional shapes described above.

[0154] Of these, the pin alignment jig 40 has a rectangular plate-like portion 40A having the same area as the second surface 20L of the base plate 20 described above, and a plurality of pin insertion holes 40B drilled in the portion at positions that coincide with the two-dimensional pin arrangement position P (see FIG. 19A) required from the design specifications. The pin alignment jig 40 also has wall portions 40C extending integrally therefrom that hang down from two (or four) opposing edges of the plate-like portion 40A. As will be described later, the size of the wall portions 40C is set so that when the jig is placed over the base plate 20, it abuts against and fits into two opposing side surfaces of the base plate 20.

[0155] 19A, the pin alignment jig 40 can be positioned relative to the base plate 20 simply by placing the pin alignment jig 40 over the base plate 20 and abutting and fitting the wall portion 40C against the side surface of the base plate 20. In other words, the multiple pin insertion holes 40B of the pin alignment jig 40 correspond to directly below in the Z-axis direction, and the position of the second surface 20U of the base plate 20 corresponds to the arrangement position P of the rod-shaped fins (pin fins) 22.

[0156] As will be described later, the assembled heat sink body 30 is pressurized from above and below in the Z-axis direction. At this time, the clamping jig 50 is a pair of pressure plates 50L, 50U (see FIGS. 19C and 19D). That is, the pressure plates 50L, 50U each clamp the tip ends 22T of the rod-shaped fins 22 of the heat sink body 30, the lower end surface of the wall portion 4C of the pin alignment jig 40, and the upper surface 20U of the base plate 20, applying pressure from both sides.

[0157] After the preparation in step S101 is completed, the pin alignment jig 40 is placed over the base plate 20 as shown in Fig. 19(A), and the rod-shaped fins 22 are inserted into the pin insertion holes 40B as shown by the dashed lines in Fig. 19(B) to set them on the pin alignment jig 40 (Fig. 17, step S102). Next, the pin alignment jig 40 is set on the base plate 20 as shown by the solid lines in Fig. 19(B) (Fig. 17, step S103). As a result, the rod-shaped fins 22 are positioned with respect to the pin arrangement position P on the surface ("lower surface 20L") of the base plate 20, and the height of the pin alignment jig 40 is adjusted so that the upper part of each rod-shaped fin 22 protrudes upward (in the length direction of the pin fins) beyond the surface of the pin alignment jig 40.

[0158] As a result, the plurality of rod-shaped fins 22 are each supported by the pin alignment jig 40 and are set upright at the pin arrangement position P on the lower surface 20L of the base plate 20.

[0159] Once this fin alignment and jig setting are complete, in step S104, as described above, the pair of the pin alignment jig 40 on which the multiple rod-shaped fins 22 are aligned and the base plate 20 is sandwiched from above and below by a pair of clamping jigs 50 (50L, 50R) (or a pressure device not shown) that function as pressure means, and setting for pressure is performed (see FIG. 19(C)). With this pressure setting, the heads of the rod-shaped fins 22 and the lower surfaces of both sides of the jig 40, i.e., the surface of the base plate 20 (lower surface 20L), are sandwiched between the pair of clamping jigs 50 (50L, 50R) so that pressure can be applied from above and below.

[0160] This pressurization is performed, for example, in a vacuum chamber VR (see FIG. 19(D)). Once preparations for pressurization are complete, in step S105, the heat sink body 30 housed in the chamber VR is pressurized while being heated at a temperature that causes a diffusion phenomenon in an atmosphere of a predetermined vacuum level, thereby performing metal bonding (see FIG. 19(D)). The heat source for heating may be placed inside or outside the chamber VR. This metal bonding includes diffusion bonding (thermal diffusion bonding, microwave bonding) as well as brazing.

[0161] For this reason, heating causes a diffusion phenomenon of atoms of the two metals at the interface between the metals (aluminum or aluminum alloy, or copper or copper alloy in this embodiment) where each rod-shaped fin 22 and the surface (lower surface 20L) of the base plate 20 come into contact with each other, and each rod-shaped fin 22 is joined (thermocompression bonded) to each other at the pin arrangement position P, thereby integrating them at the atomic level. Note that if the rod-shaped fins 22 and the base plate 20 are made of different materials (e.g., aluminum or aluminum alloy and copper or copper alloy), the joining described above may result in a layered joint, and some voids may occur in the layer. In this regard, in this embodiment, the rod-shaped fins 22 and the base plate 20 are made of the same material (aluminum or aluminum alloy), so that such voids can be reduced and a more reliable joining at the atomic level can be achieved.

[0162] Therefore, a heat sink body 30 is formed in which the rod-shaped fin assembly stands upright from the lower surface 20L of the base plate 20 and the two elements of the rod-shaped fins and the base plate are integrated with each other. The rod-shaped fin assembly is provided in a state of protruding toward the cooling space SP through which the refrigerant passes.

[0163] An example of the bonding conditions for the thermal diffusion bonding in step S105 is as follows: when the base plate 20 and the rod-shaped fins 22 are made of aluminum, the pressure is 0.05 to 40 MPa, and the vacuum degree is 10 -4 ~10 -5 Torr, heating temperature = 264 to 396°C, heating time = 60 to 400 min. Of course, other joining conditions may be set. Furthermore, when the base plate 20 and the rod-shaped fins 22 are made of aluminum, the joining conditions are, for example, pressure = 0.01 to 40 MPa, vacuum = 10, taking into account the melting point of copper, etc. -4 ~10 -5 Torr, heating temperature = 650 to 1050°C, heating time = 1 to 400 min.

[0164] Once the thermal bonding is complete, in step S106, the integrated heat sink body 30 is removed from the chamber VR and undergoes an inspection process (not shown) before the cooling device 1 is assembled. If the base plate 20 and the rod-shaped fins 22 are both made of copper or a copper alloy and the cover 14 is made of aluminum, the heat sink body 30 is subjected to a corrosion-resistant surface treatment, such as nickel plating, after removal. This plating layer provides corrosion protection against rust caused by copper ions dissolving in the fluid (refrigerant) and natural electrode potential differences. In particular, nickel plating is applied to the portion of the base plate 20 that contacts the cover 14, the underside 20L of the base plate 20 exposed to the cooling space SP, the rod-shaped fins 22, and the surface of the aluminum cover 14 exposed to the cooling space SP.

[0165] As described above, the heat sink body 30 according to this embodiment is formed by, for example, diffusion bonding (thermocompression bonding) a plurality of pre-prepared rod-shaped fins (pin fins) 22 to the base plate 20. This makes it easier to form a simple integrated structure consisting of the rod-shaped fins 22 and the base plate 20. Therefore, design specifications required to exhibit sufficient cooling performance, such as the shape and height of the rod-shaped fins 22 and their arrangement density on the base plate 20, can be realized more easily and at lower cost than with conventional processing methods such as die casting.

[0166] Of course, instead of the diffusion bonding, a bonding method such as brazing can also be used.

[0167] <Modification 10> Modification 10, which is applicable to the above-described embodiments and their modifications, will be described with reference to Fig. 20. This example relates to a corrosion prevention structure for a rod-shaped fin-type heat sink.

[0168] Conventionally, pin fin or plate fin heat sinks have been manufactured by forging, casting, or by adding machining to these methods. In other words, since they are manufactured from the same base material from the beginning, the natural electrode potential E (also called corrosion potential or natural potential) of the parts that make up the fins and base plate is the same.

[0169] It is generally known that corrosion pits form over time in the fins and base plate due to the corrosive components of the coolant or cooling water flowing through the heat sink (schematically shown by the reference symbol CO in Figure 20). If the corrosion progresses to the point where the corrosion pit CO penetrates the base plate, it is expected that coolant or cooling water leakage will occur, significantly impairing cooling performance and reducing the functionality of the electronic components being cooled. Such a situation can lead to a breakdown in the reliability of the electronic components in question, and therefore should be avoided, at least during the warranty period.

[0170] The inventors have considered that such corrosion-related problems are one of the problems resulting from the conventional method of integrally molding the fins and base plate from the beginning. Therefore, the inventors have conceived the idea that another advantage of preparing the fins and base plate as separate components, as in the present invention, is that the progression of such corrosion can be controlled between the fins and the base plate. As a specific solution, in the preparation process of step S101 in the above-mentioned manufacturing method, when the rod-shaped fins 22 and the base plate 20 are separately prepared, elements such as ZN (zinc), SN (tin), and LN (lanthanides) are added to the aluminum (Al) material of the rod-shaped fins 22 to form the rod-shaped fins 22 as an aluminum alloy. In this case, for example, the base plate 20 is formed from aluminum or an aluminum alloy. This electrochemically lowers the natural electrode potential EF of the rod-shaped fins 22 (aluminum alloy) compared to the natural electrode potential EP of the base plate 20 (EF < EP: noble potential). For example, the natural electrode potential of the rod-shaped fins 22 is set to be less noble than the natural electrode potential of the base plate 20 by a potential (e.g., 100 mV) selected from a predetermined potential range (e.g., 20 to 200 mV). According to this example, the rod-shaped fins 22 and the base plate 20 are prepared separately and then integrated by bonding, making it easy to set the above-mentioned relationship EF<EP.

[0171] Therefore, even if the above-mentioned corrosion pitting CO occurs in both the rod-shaped fins 22 and the base plate 20 with use over time, the corrosion rate of the base plate 20 is slower than that of the rod-shaped fins 22. Since a large number of rod-shaped fins 22 are typically installed upright, even if corrosion occurs in a small number of these rod-shaped fins 22, it is unlikely that cooling performance will be significantly reduced. Instead, by subjecting the rod-shaped fins 22 to sacrificial corrosion while delaying the occurrence of corrosion pitting CO in the base plate 20, the life of the base plate 20 is extended against corrosion pitting, and the high cooling performance of the rod-fin heat sink 12 can be maintained for a long period of time. Additionally, corrosion-resistant surface treatment (e.g., anodizing) can be omitted.

[0172] As described above, various embodiments and modifications of the rod-shaped fin heat sink according to the present disclosure have been described, but the present invention is not necessarily limited to the configurations described therein. Furthermore, conventionally known structures can be implemented by combining manufacturing processes, and even in such cases, as long as the gist of the claims 1 and 26 is not deviated from, it falls within the scope of rights sought by those claims.

[0173] 1: Cooling device 12, 12A to 12J: Pin fin heat sink as rod-shaped fin heat sink 14: Cover 18: Piping 19: Fluid source (fluid supply device) 20 Base plate (base portion) 20U Upper surface 20L Lower surface 22, 221, 221h, 222, 223, 22D to 22J Rod-shaped fins 22T Tip portion 22R Lower end portion 30 Heat sink body (part of pin fin heat sink) PK1 to PK3: Electronic element package C1 to C3: Cooling area S1, S2: Separation area IT: Inlet area ET: Outlet area EL, ER: Side area FL: Cooling fluid Y: Y-axis direction (flow direction of fluid FL) X: X-axis direction (lateral direction)

Claims

1. A rod-shaped fin heat sink that dissipates heat generated from a package enclosing an electronic element in association with the operation of the electronic element through heat exchange with a forcibly supplied cooling fluid, comprising: first and second rod-shaped fins having thermal conductivity; and a thermally conductive base portion on which the first and second rod-shaped fins are erected; the base portion is capable of contacting a plurality of the packages and has a first surface that absorbs the heat generated by the electronic element and a second surface that faces back-to-back with the first surface and to which the heat is transferred; a plurality of cooling areas for cooling each of the plurality of packages are set in a vertical row on the second surface along a predetermined direction in which the cooling fluid flows; and each of the plurality of cooling areas is provided with a fin assembly consisting of a plurality of the first rod-shaped fins based on the cooling capacity required for each of the plurality of packages; a rod-shaped fin type heat sink, characterized in that: a side area adjacent to the plurality of cooling areas is set on each of both sides of the second surface in a horizontal direction intersecting the predetermined direction, and a plurality of the second rod-shaped fins are erected in each of the side areas on both sides for controlling the flow of the cooling fluid so that the cooling fluid is directed toward the plurality of cooling areas.

2. The rod-shaped fin heat sink as described in claim 1, characterized in that the second surface is provided with an inlet area through which the cooling fluid enters from the outside and an outlet area through which the cooling fluid is output to the outside, and a separation area is provided in which the multiple cooling areas are separated from each other by a certain distance in the specified direction, and the cooling fluid is configured to flow from the inlet area, through the multiple cooling areas and the separation area, toward the outlet area along the specified direction.

3. The rod fin heat sink of claim 2, characterized in that the inlet area, the outlet area, and the separation area on the second surface are configured to flow the cooling fluid along a portion of the second surface itself, and are areas that do not have rod fins that come into contact with the cooling fluid.

4. A rod-shaped fin type heat sink as described in claim 2, characterized in that a plurality of third rod-shaped fins are provided upright in at least one of the inlet area and the separation area on the second surface, which come into contact with the flow of the cooling fluid and bias the flow of the fluid into the next cooling area.

5. The rod-shaped fin heat sink as described in claim 4, characterized in that each of the first rod-shaped fin, the second rod-shaped fin, and the third rod-shaped fin is an elongated rod extending from the second surface in the longitudinal direction of the fin, and the cross-sectional shape perpendicular to the longitudinal direction is a circle, a polygon, or an ellipse.

6. The rod-shaped fin heat sink as described in claim 4, characterized in that the first rod-shaped fin is a rod-shaped fin having an elliptical cross-sectional shape along the height direction of the first rod-shaped fin, the second rod-shaped fin is a rod-shaped fin having a rectangular cross-sectional shape along the height direction of the second rod-shaped fin, and the third rod-shaped fin is a rod-shaped fin having a circular cross-sectional shape along the height direction of the third rod-shaped fin.

7. The rod fin heat sink as described in claim 4, characterized in that the first and third rod fins have the same cross-sectional shape along the height direction of each of the first and third rod fins, and the cross-sectional shape is elliptical or circular, and the second rod fin has a cross-sectional shape along the height direction of the second rod fin that is rectangular.

8. The rod fin heat sink of claim 6, wherein the ratio of the major and minor axes of the elliptical and rectangular cross sections or the aspect ratio of the cross sections is 5:1 or less.

9. The rod fin heat sink according to claim 8, wherein the elliptical rod fins are arranged such that the major axis of the rod fins is oriented along the predetermined direction.

10. The rod-shaped fin heat sink as described in claim 1, characterized in that the second rod-shaped fin is an elongated rod extending from the second surface in the longitudinal direction of the fin and has a rectangular cross-sectional shape perpendicular to the longitudinal direction, and the second rod-shaped fin is arranged so that a line virtually extending from one side of the rectangle intersects obliquely at a predetermined angle with respect to the predetermined direction in a plan view.

11. A rod-shaped fin heat sink as described in claim 10, characterized in that the second rod-shaped fins are arranged at the same density regardless of their position along the specified direction, or at a density that decreases the further downstream in the specified direction.

12. The rod-shaped fin heat sink according to claim 4, characterized in that: the first rod-shaped fins are rod-shaped fins having an elliptical cross-sectional shape, the first rod-shaped fins are arranged in a vertical row with a plurality of fins per row in the specified direction in each of the plurality of cooling areas, and adjacent rows in the horizontal direction are arranged in a staggered pattern with respect to each other; and the third rod-shaped fins are rod-shaped fins having a circular cross-sectional shape, the third rod-shaped fins are arranged in a vertical row in the specified direction in each of the entrance area, the exit area, and the separation area, and each of the multiple rows of the third rod-shaped fins is aligned in the horizontal direction with the row of the first rod-shaped fins of which a leading rod-shaped fin is advancing in the specified direction among the multiple rows of the first rod-shaped fins.

13. A rod-fin type heat sink as described in any one of claims 1 to 7 and 9 to 12, characterized in that the multiple cooling areas require the same amount of heat exchange.

14. A rod-fin type heat sink as claimed in any one of claims 1 to 7 and 9 to 12, characterized in that the amount of heat exchange required for the multiple cooling areas differs from one another.

15. The rod-shaped fin heat sink as described in claim 14, characterized in that the heat exchange capacities = QS1, QS2, and QS3 are set by changing at least one of the longitudinal length of each rod-shaped fin, the cross-sectional size, and the arrangement density per unit area of ​​the multiple rod-shaped fins.

16. The rod-shaped fin heat sink as described in claim 14, characterized in that the multiple cooling areas are three cooling areas numbered first to third, in which the heat exchange amounts are relatively "QS1", "QS2", and "QS3" (QS1>QS2, QS3: QS2>QS3), and the first to third cooling areas are arranged in the order of the first, second, and third cooling areas from the upstream side in the specified direction, and the second surface is provided with two separation areas, first and second, which spatially separate two cooling areas adjacent to each other in the flow direction among the three cooling areas numbered first to third.

17. A rod-shaped fin heat sink as described in any one of claims 2 to 7 and 9 to 12, characterized in that the specified direction is a linear direction from the inlet area to the outlet area, and the inlet area and the outlet area are formed directly opposite each other in the specified direction on the second surface of the base portion.

18. A rod-shaped fin type heat sink as described in any one of claims 2 to 7 and 9 to 12, characterized in that a group of rod-shaped fins are erected in a flow path in which the cooling fluid flows from the inlet area to the outlet area on the second surface of the base portion, along the flow path that changes the flow direction of the cooling fluid, so as to change the flow direction of the cooling fluid.

19. The rod fin heat sink of claim 18, wherein the converting flow passage is a curved flow passage formed in a portion of the second surface that bends the flow of the cooling fluid entering through the inlet area and directs the cooling fluid through the cooling area.

20. A rod-shaped fin heat sink as described in claim 4, wherein at least the first rod-shaped fin and the third rod-shaped fin, among the first rod-shaped fin, the second rod-shaped fin and the third rod-shaped fin, are formed so that the size of their cross sections perpendicular to the longitudinal direction increases as they progress from the second surface in the longitudinal direction to the fin tip.

21. A rod-shaped fin heat sink as described in any one of claims 1 to 7 and 9 to 12, characterized in that the natural electrode potential of at least the first rod-shaped fin relative to the natural electrode potential of the base portion is set to be electrochemically baser.

22. A cooling device comprising: a rod-shaped fin heat sink as defined in any one of claims 2 to 7 and 9 to 21; and fluid circulation means for circulating the cooling fluid through the rod-shaped fin heat sink to effect the heat exchange between the rod-shaped fins of the heat sink and the cooling fluid.

23. The cooling device described in claim 22, characterized in that the fluid circulation means comprises: a case which cooperates with the second surface of the base portion to surround the assembly of the multiple rod-shaped fins standing on the second surface and form a space for flowing the heat exchange fluid between the multiple rod-shaped fins; piping attached to the case and for circulating the fluid; and a fluid source which circulates the fluid through the piping and the space.

24. The cooling device described in claim 23, characterized in that the piping has an inlet end connected to the inlet area and an outlet end connected to the outlet area, and the inlet end and the outlet end are located directly opposite each other in the specified direction or offset from each other in the lateral direction.

25. A method for manufacturing a rod-shaped fin heat sink as defined in claim 1, comprising: a first step of setting a pin alignment jig, having a plurality of through holes formed therein that correspond to the diameters and erect positions of the rod-shaped fins, on the base portion so as to face the second surface, and inserting the rod-shaped fins into the plurality of through holes so that one end of each of the rod-shaped fins protrudes from the plurality of through holes; a second step of setting a pressure jig that applies pressure between the first surface of the base portion and one ends of each of the rod-shaped fins protruding from the plurality of through holes in the pin alignment jig; a third step of diffusion bonding or brazing bonding the other ends of each of the pins to the second surface of the base portion while applying pressure with the pressure jig; and a fourth step of removing the pin alignment jig from the rod-shaped fins after the third step.

26. In the manufacturing method of a rod-shaped fin heat sink as described in claim 25, the first step is characterized by comprising: a pin plate preparation step of preparing the rod-shaped fins and the base portion as separate parts; a jig setting step of first setting the pin alignment jig on the base portion; and a tweezers step of, after setting the pin alignment jig on the base portion, inserting the rod-shaped fins into the multiple through holes of the pin alignment jig, respectively, to prepare a state in which one end of each of the rod-shaped fins protrudes from the multiple through holes.

Images