Boiling cooler

Abstract

This boiling-type cooler (100) comprises: a boiling unit (10) that has a storage space (11) for storing a refrigerant (1), said boiling unit (10) boiling the refrigerant by exchanging heat with a heating element (HS); and a condensing unit (20) that communicates with the boiling unit and condenses refrigerant gas (1a) from the boiling unit by exchanging heat with an external fluid (2). The boiling unit: is formed in a plate shape having an upper surface (12) and a lower surface (13), each having a heating element installed thereon; and is provided so as to extend diagonally downward from a portion (30) connecting to the condensing unit.

Description

[Technical Field]

[0001] The present invention relates to a boiling type cooler, and more particularly to a boiling type cooler in which a refrigerant is circulated between a boiling section that boils the refrigerant and a condensing section that condenses the vaporized refrigerant. [Background technology]

[0002] BACKGROUND ART Conventionally, a boiling type cooler in which a refrigerant is circulated between a boiling part and a condensing part has been known. Such a boiling type cooler is disclosed, for example, in Japanese Patent Application Laid-Open No. 2002-134670.

[0003] The above-mentioned Japanese Patent Application Laid-Open No. 2002-134670 discloses a structure in which a condenser consisting of a plate-fin heat exchanger in an inverted T shape is joined to the upper surface of a horizontally arranged evaporator (boiler). A refrigerant is sealed inside the evaporator. A plate for mounting semiconductor elements is provided on the lower surface of the evaporator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-134670 Summary of the Invention [Problem to be solved by the invention]

[0005] In this specification, a boiling type cooler whose boiling portion extends horizontally, such as the boiling type cooler disclosed in Japanese Patent Application Laid-Open No. 2002-134670, is referred to as a "horizontal" boiling type cooler. In a horizontal boiling type cooler, a heat generating element needs to be installed on the lower surface of the boiling portion. This is because, inside the boiling portion, liquid-phase refrigerant accumulates in the lower part and gas-phase refrigerant gas accumulates in the upper part, making it difficult to obtain sufficient cooling performance even if a heat generating element is installed on the upper surface of the boiling portion. Therefore, a horizontal boiling type cooler has a problem in that it is difficult to secure an installation area for the heat generating element.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a boiling type cooler that allows the installation area of the heating element to be increased even if it is a horizontal boiling type cooler. [Means for solving the problem]

[0007] In order to achieve the above object, a boiling type cooler according to the present invention comprises a boiling section having an accommodating space for accommodating a refrigerant and boiling the refrigerant by heat exchange with a heating element, and a condensing section communicating with the boiling section and condensing the refrigerant gas from the boiling section by heat exchange with an external fluid, wherein the boiling section is formed in a plate shape having upper and lower surfaces on which the heating element is disposed, and is provided so as to extend obliquely downward from a connection portion with the condensing section; The storage space further includes a partition plate that divides the storage space into an upper space adjacent to the upper surface and a lower space adjacent to the lower surface, The condensation section is provided so as to extend upward from the upper surface of the boiling section, and a through-hole is formed on the upper surface of the boiling section to communicate between the storage space and the condensation section, and the through-hole is configured to allow refrigerant gas to flow into the condensation section and allow condensed refrigerant to flow into the storage space. The partition plate is provided over the entire storage space, and in a region that overlaps vertically with the through-hole on the top surface, a first communication passage that passes through the partition plate and connects the upper space and the lower space. do.

[0008] In the boiling type cooler according to the present invention, as described above, the boiling portion extends obliquely downward from the connection portion with the condensing portion. This allows the inner upper surface of the refrigerant storage space to be inclined relative to the liquid refrigerant level, allowing the inner upper surface of the storage space to be continuously in contact with the liquid refrigerant. The condensing portion extends upward from the upper surface of the boiling portion. The upper surface of the boiling portion is formed with a through-hole that connects the storage space and the condensing portion. The through-hole is configured to allow refrigerant gas to flow into the condensing portion and condensed refrigerant to flow into the storage space. Since the storage space is inclined upward toward the condensing portion, refrigerant gas vaporized within the storage space moves along the inclined storage space toward the condensing portion. This prevents excessive stagnation of refrigerant gas on the inner upper surface of the storage space. As a result, sufficient cooling performance can be achieved even for a heat-generating element placed on the upper surface of the boiling portion. Therefore, by allowing the heat-generating element to be placed on both the upper and lower surfaces of the boiling portion, the installation area for the heat-generating element can be increased, even in a horizontal boiling type cooler. The boiling portion further includes a partition plate that divides the storage space into an upper space adjacent to the upper surface and a lower space adjacent to the lower surface. With this configuration, the partition plate prevents refrigerant gas generated in the lower space of the storage space due to heat absorption from a heat-generating element installed on the lower surface of the boiling portion from migrating to the upper space. This prevents all refrigerant gas from concentrating on the interior upper surface of the storage space (upper space), preventing contact between the refrigerant and the interior upper surface. This improves the cooling performance of the heat-generating element on the upper surface of the boiling portion. It is also known that in heat exchangers, a state in which a moderate ratio of liquid and gas phases exists on the heat transfer surface improves cooling performance due to the evaporation of a liquid film along the heat transfer surface, rather than a state in which the heat transfer surface is completely filled with liquid. Therefore, if the partition plate blocks refrigerant gas generated in the lower space, resulting in a moderate ratio of liquid and gas phases on the interior upper surface of the upper space, more effective improvement in cooling performance on the upper surface can be expected. The partition plate is provided over the entire storage space, and in a region vertically overlapping with the through-hole on the upper surface, a first communication passage penetrates the partition plate to connect the upper space and the lower space. With this configuration, the partition plate is provided over the entire storage space, thereby reliably preventing refrigerant gas generated in the lower space from collecting on the interior upper surface of the storage space. Furthermore, the refrigerant gas generated in the lower space moves along the partition plate, allowing the refrigerant gas in the lower space to pass through the first communication passage and move toward the condensation section. This eliminates the need to form a passage in the boiling section separate from the partition plate for moving the refrigerant gas in the lower space to the condensation section, simplifying the structure of the boiling-type cooler.In this specification, a horizontal boiling type cooler includes a case where the boiling part is inclined from the horizontal direction as long as the horizontal dimension of the boiling part is greater than the vertical dimension of the boiling part. In other words, if the boiling part has a simple flat plate shape and is provided at an angle of less than 45 degrees to the horizontal direction, it is included in the "horizontal" boiling type cooler.

[0009] In the above invention, the boiling portion is preferably inclined so that the liquid level of the refrigerant is located within or above the area where the heating element is installed on the upper surface. This configuration allows the area of the interior upper surface of the storage space facing the area where the heating element is installed (the area directly below the heating element) to come into contact with the liquid refrigerant. This prevents the area directly below the heating element from partially drying out, effectively preventing local temperature increases (local reductions in cooling performance). Dryout occurs when the liquid refrigerant disappears from the heat transfer surface and the heat transfer surface is covered with gaseous refrigerant (a single-phase vapor state). This significantly reduces the heat transfer coefficient in the area where dryout occurs.

[0010] In the above invention, preferably, the boiling portion is inclined at an angle of 5 degrees or more and less than 45 degrees with respect to the horizontal direction. With this configuration, it is possible to obtain a horizontal boiling type cooler in which the height dimension of the boiling type cooler can be reduced, while also being able to install a heating element on the upper surface of the boiling portion, thereby increasing the installation area of the heating element.

[0011] In the above-described configuration in which the boiling portion includes a partition plate, a second communication passage that connects the upper space and the lower space is preferably formed at one end located on the lower side of the storage space. With this configuration, even if the storage space is partitioned into the upper space and the lower space, the liquid phase refrigerant can be moved through the second communication passage. Therefore, the refrigerant is not unevenly stored in either the upper space or the lower space, and the amount of refrigerant stored in the upper space and the lower space can be made uniform.

[0012] In the above invention, the condensing section preferably has a flow passage for an external fluid that penetrates the condensing section horizontally. With this configuration, even if the boiling section is tilted diagonally downward, the condensing section extends vertically, allowing the external fluid to be fed horizontally to the condensing section. For example, when condensing the refrigerant gas in the condensing section by forced cooling using a driving source to feed the external fluid, it is not necessary to tilt the driving source or the flow passage for the external fluid to match the inclination of the boiling section. Therefore, when combining the boiling type cooler with an external device, the boiling type cooler can be easily adapted to the external device. [Effects of the Invention]

[0013] According to the present invention, as described above, even in the case of a horizontal boiling type cooler, the installation area of the heating element can be increased. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic perspective view showing an overall configuration of a cooler according to an embodiment; [Figure 2] 2 is a schematic longitudinal sectional view of the cooler of FIG. 1 taken along the YZ direction. [Figure 3] FIG. 2 is a schematic longitudinal cross-sectional view along the EZ direction showing the internal structure of the boiling portion. [Figure 4] FIG. 2 is a schematic enlarged longitudinal cross-sectional view of the boiling portion along the X direction. [Figure 5] FIG. 2 is a schematic plan view showing the upper surface of the boiling portion. [Figure 6] FIG. 2 is a schematic plan view showing a partition plate. [Figure 7] FIG. 4 is a schematic cross-sectional view showing a second member of the boiling portion. [Figure 8] FIG. 4 is a schematic diagram illustrating the operation of a cooler according to an embodiment. [Figure 9] FIG. 10 is a schematic longitudinal cross-sectional view of a boiling portion according to a reference example taken along the EZ direction. [Figure 10] FIG. 10 is a schematic longitudinal cross-sectional view of a boiling portion according to a reference example taken along the X direction. [Figure 11]10A and 10B are schematic diagrams for explaining the operation of a cooler in a reference example. [Figure 12] FIG. 10 is a schematic diagram showing a boiling portion according to a comparative example. [Figure 13] 1 is a graph showing experimental results 1 for a heat generation amount of 50% according to an embodiment. [Figure 14] 10 is a graph showing experimental results 2 for a heat generation amount of 100% according to an embodiment. [Figure 15] 10 is a graph showing experimental results 3 for a heat generation amount of 150% according to an embodiment. [Figure 16] 16 is a graph summarizing the experimental results shown in FIGS. 13 to 15. [Figure 17] 10A and 10B are schematic diagrams showing modified examples of the orientation of the condensation section. [Figure 18] 10A and 10B are schematic diagrams showing modified examples of the inclination angle of the boiling portion. [Figure 19] 10A and 10B are schematic diagrams showing modified examples of the range in which the partition plate is formed. [Figure 20] FIG. 10 is a schematic diagram showing a modified example in which a through hole is formed in the partition plate. [Figure 21] 10A and 10B are schematic diagrams showing modified examples of the first communicating portion and the second communicating portion. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0016] [ One embodiment ] With reference to FIGS. 1 to 8, One embodiment The configuration of a boiling type cooler 100 (hereinafter referred to as cooler 100) based on this method will be described. The cooler 100 is a boiling cooling type cooler that uses the phase change between vaporization and condensation of a refrigerant to absorb heat from a heat-generating body HS and release the heat to the outside. The cooler 100 cools the heat-generating body HS by heat absorption by the refrigerant. The refrigerant gas that has vaporized due to heat absorption is cooled by an external fluid, condenses, and returns to a liquid phase.

[0017] The heating element HS is not particularly limited. For example, the heating element HS is a device equipped with an electronic circuit. Specifically, the heating element HS is a power module constituting a power conversion circuit such as an inverter device. The power module is a circuit component equipped with one or more power conversion switching elements. The power conversion switching elements are, for example, IGBT (insulated gate bipolar transistor) elements.

[0018] (Overall configuration of the cooler) As shown in Fig. 1, cooler 100 includes boiling section 10, condensing section 20, and connecting section 30. A space (see Fig. 2) for accommodating refrigerant 1 is formed inside each of boiling section 10, condensing section 20, and connecting section 30. Cooler 100 has an internal space sealed by boiling section 10, condensing section 20, and connecting section 30. Refrigerant 1 is accommodated in this sealed space. Boiling section 10, condensing section 20, and connecting section 30 are made of a metal material with high thermal conductivity, such as aluminum (including aluminum alloys) or copper (including copper alloys).

[0019] The refrigerant 1 is not particularly limited as long as it changes phase between gas and liquid. Therefore, the refrigerant 1 may be selected from known refrigerants depending on the heating element HS, and examples thereof include fluorocarbons, hydrocarbons, and water. The internal space of the cooler 100 is depressurized to a substantially vacuum state, and the gas-phase refrigerant 1 is in a saturated vapor state. For convenience, when distinguishing between the states of the refrigerant 1, the gas-phase refrigerant 1 is referred to as refrigerant gas 1a (see FIG. 2), and the liquid-phase refrigerant 1 is referred to as refrigerant liquid 1b (see FIG. 2).

[0020] In the following, two directions that are perpendicular to each other in a horizontal plane are referred to as the X direction and the Y direction, respectively. The vertical direction that is perpendicular to the horizontal plane (XY plane) is referred to as the Z direction. Note that the Z direction is approximately parallel to the direction of gravity, and gravity acts downward. As will be described later, the direction in which the boiling portion 10 extends is referred to as the E direction. In the following description, the E direction is included in the YZ plane and is inclined downward at an angle θ with respect to the Y direction.

[0021] In the example shown in FIG. 1, four heating element HS installation areas are provided on the upper surface 12 of the boiling portion 10, and four heating element HS installation areas are provided on the lower surface 13 of the boiling portion 10. That is, on each of the upper surface 12 and the lower surface 13, there are two columns of installation areas in the X direction and two rows in the Y direction (strictly speaking, the E direction). The cooler 100 has a structure in which a plurality of unit structures SU are arranged in the X direction, with each column being a unit structure SU. Each unit structure SU has substantially the same structure. Therefore, the following will describe one unit structure SU. Note that while FIG. 1 shows an example configuration including two unit structures SU, the cooler 100 may include only one unit structure SU, or three or more unit structures SU.

[0022] A heating element HS is installed in the boiling portion 10. As shown in FIG. 2, the boiling portion 10 has a storage space 11 that stores the refrigerant 1. Refrigerant liquid 1b is stored in the storage space 11 of the boiling portion 10 by the action of gravity. The boiling portion 10 is configured to boil the refrigerant 1 (refrigerant liquid 1b) by heat exchange with the heating element HS. The boiling portion 10 has an upper surface 12 and a lower surface 13. The boiling portion 10 has two side surfaces 14 (see FIG. 1) on both sides in the X direction, and an end surface 15 at one end E1 and an end surface 16 at the other end E2 in the E direction. The boiling portion 10 has a plate-like shape including the upper surface 12, the lower surface 13, the two side surfaces 14, and the two end surfaces 15, 16.

[0023] An installation area for the heating element HS is provided on one end E1 side of the boiling portion 10. The condensation portion 20 is connected to the other end E2 side of the boiling portion 10 via a connection portion 30. The boiling portion 10 is provided so as to extend obliquely downward from the connection portion with the condensation portion 20 (i.e., connection portion 30). The boiling portion 10 is provided so as to be inclined downward at an angle θ with respect to the horizontal direction (Y direction). As a result, the boiling portion 10 extends linearly in the E direction, which is obliquely downward from the connection portion with the condensation portion 20. A through hole 12a is formed in the upper surface 12 of the boiling portion 10, connecting the storage space 11 and the condensation portion 20.

[0024] The connecting portion 30 has a cylindrical shape extending in the Z direction. The lower end surface of the connecting portion 30 is joined to the upper surface 12 of the boiling portion 10, and the upper end surface of the connecting portion 30 is joined to the lower surface of the condensing portion 20. The lower end surface of the connecting portion 30 is inclined at an angle θ to match the upper surface 12 of the boiling portion 10, which is inclined obliquely downward. The upper end surface of the connecting portion 30 is along a horizontal plane (XY plane). The connecting portion 30 is provided so as to surround the through-hole 12a formed in the upper surface 12 of the boiling portion 10. The connecting portion 30 provides an airtight connection between the storage space 11 of the boiling portion 10 and the storage space 21a of the condensing portion 20.

[0025] The connection portion 30 constitutes a passage through which the refrigerant gas 1a vaporized in the boiling portion moves to the condensing portion 20, and also constitutes a passage through which the refrigerant liquid 1b condensed in the condensing portion 20 moves to the boiling portion . This embodiment In this type of cooler, the movement path of refrigerant gas 1a and the movement path of refrigerant liquid 1b are the same. In other words, the boiling section 10 and the condensing section 20 are connected by a single passage (connection section 30). In the single passage (connection section 30), the refrigerant gas 1a moving to the condensing section 20 and the refrigerant liquid 1b moving to the boiling section 10 are in a gas-liquid mixed phase state. Therefore, the device structure can be simplified compared to a type of cooler that forms a loop-shaped internal space in which the boiling section 10 and the condensing section 20 are separately connected by a passage dedicated to refrigerant gas 1a and a passage dedicated to refrigerant liquid 1b.

[0026] The condensing section 20 is provided to extend upward from the upper surface 12 of the boiling section 10 via the connecting section 30. The condensing section 20 is in communication with the boiling section 10 via the connecting section 30. The condensing section 20 is configured to condense the refrigerant gas 1a from the boiling section 10 by heat exchange with the external fluid 2.

[0027] The condensation section 20 has an accommodating space 21a that accommodates a refrigerant 1. As shown in FIG. 1, the condensation section 20 has a flow passage 22 for an external fluid 2 that penetrates the condensation section 20 in the horizontal direction (Y direction). The flow passage 22 is a passage that is open to the outside of the condensation section 20. The accommodating space 21a (see FIG. 2) is an internal space of the condensation section 20 that is surrounded by a wall section 24 that partitions the flow passage 22. In other words, the accommodating space 21a and the flow passage 22 are partitioned by the wall section 24 that configures the condensation section 20 so that they do not communicate with each other. The accommodating space 21a (see FIG. 2) is provided inside the refrigerant accommodating section 21 in FIG. 1.

[0028] In the condenser 20, a plurality of refrigerant containing sections 21 and a plurality of circulation passages 22 are arranged alternately in the X direction. Corrugated fins 23 are provided in the circulation passages 22 from one end to the other in the Y direction. The external fluid 2 passing through the circulation passages 22 is air. As shown in FIG. 2 , when the cooler 100 is in operation, a blower 3 is provided as a driving source for the external fluid 2, which blows air in the Y direction along the circulation passages 22.

[0029] The storage space 21a is open on the lower side in the Z direction, and is surrounded on the upper side in the X, Y, and Z directions by a wall portion 24. The lower end of the wall portion 24 is joined to the upper end of the connection portion 30. The open lower surface side of the storage space 21a communicates with the storage space 11 of the boiling portion 10 via the connection portion 30. Therefore, the cooler 100 has a closed internal space composed of the storage space 11 of the boiling portion 10, the interior of the connection portion 30, and the storage space 21a of the condensing portion 20. A refrigerant 1 is sealed in this internal space.

[0030] Fins 25 extending in the Z direction are provided in the accommodation space 21a.

[0031] As shown in Fig. 2, refrigerant gas 1a vaporized in boiling section 10 flows through connection section 30 into storage space 21a of condensing section 20, where it diffuses upward through fins 25. Condensing section 20 transfers the heat of refrigerant gas 1a that has flowed into storage space 21a to external fluid 2 passing through flow passage 22 (see Fig. 1), causing refrigerant gas 1a to condense (liquefy). Refrigerant liquid 1b condensed by heat exchange with external fluid 2 is returned to boiling section 10 through connection section 30, mainly due to the action of gravity.

[0032] As a result, inside the cooler 100, the refrigerant 1 circulates between the boiling section 10 and the condensing section 20 so as to repeat a cycle of phase change between vaporization of the refrigerant 1 in the boiling section 10 and condensation of the refrigerant 1 in the condensing section 20.

[0033] (Inclination angle of boiling part) As shown in Figure 2, This embodiment In the boiling portion 10, the liquid level 1c of the refrigerant 1 (refrigerant liquid 1b) is inclined so that it is located within the installation area of the heating element HS on the upper surface 12. In other words, the liquid level 1c is located in a height range between the lower end position and the upper end position of the installation area of the heating element HS on the upper surface 12. Specifically, the liquid level 1c is located at a height that approximately coincides with the upper end of the installation area of the heating element HS on the upper surface 12. The position of the liquid level 1c is the position when the cooler 100 is in a non-operating state. The installation area is the area on the upper surface 12 that is covered by the heating element HS when the heating element HS is installed (the so-called footprint). The boiling portion 10 is inclined at an inclination angle θ of 5 degrees or more and less than 45 degrees with respect to the horizontal. In the example of FIG. 2, the inclination angle θ is 10 degrees.

[0034] (Boiling section structure) Next, the structure of the boiling portion 10 will be described in detail with reference to Figures 3 to 7. As shown in Figure 3, the boiling portion 10 is configured in a hollow, flat plate shape by joining lid members 43 to one end E1 and the other end E2 of a cylindrical case member 40. The case member 40 has an upper surface 12, a lower surface 13, and two side surfaces 14 (see Figure 1). The two lid members 43 form an end surface 15 of the one end E1 and an end surface 16 of the other end E2. The case member 40 includes an upper first member 41 including the upper surface 12, and a lower second member 42 including the lower surface 13.

[0035] The storage space 11 is formed to extend in the E direction from one end E1 to the other end E2 of the boiling portion 10. Hereinafter, the inner surface of the storage space 11 on the upper surface 12 side is referred to as the inner upper surface 41a, and the inner surface of the storage space 11 on the lower surface 13 side is referred to as the inner lower surface 42a. The inner upper surface 41a is the inner surface of the first member 41, and the upper surface 12 is the outer surface of the first member 41. The inner lower surface 42a is the inner surface of the second member 42, and the lower surface 13 is the outer surface of the second member 42. A through-hole 12a is formed in the first member 41 to communicate the storage space 11, the interior of the connection portion 30 (see FIG. 2), and the storage space 21a (see FIG. 2) of the condenser portion 20. The through-hole 12a penetrates the first member 41 from the upper surface 12 to the inner upper surface 41a.

[0036] This embodiment In the boiling portion 10, the boiling portion 10 further includes a partition plate 44 that divides the accommodation space 11 into an upper space 11a adjacent to the upper surface 12 and a lower space 11b adjacent to the lower surface 13. The partition plate 44 is a flat plate member extending along the E direction. As shown in FIG. 4, the partition plate 44 is provided so as to be sandwiched between the first member 41 and the second member 42.

[0037] The partition plate 44 divides the storage space 11 into two spaces: an upper space 11a and a lower space 11b. The partition plate 44 is disposed parallel to the upper surface 12 and the lower surface 13. Therefore, the upper space 11a and the lower space 11b extend in the E direction and are disposed parallel to each other. The upper space 11a and the lower space 11b are both formed to extend in the E direction from one end E1 of the boiling portion 10 to the other end E2. In the example of FIG. 4, the partition plate 44 divides the storage space 11 into two equal spaces. That is, in the thickness direction of the boiling portion 10, the height h1 of the upper space 11a and the height h2 of the lower space 11b are equal.

[0038] 3, the partition plate 44 is provided in at least an area OA that overlaps in the thickness direction of the boiling section 10 with the area on the upper surface 12 where the heating element HS is installed. The area on the upper surface 12 where the heating element HS is installed has a length L1 in the E direction and a width W1 (see FIG. 5) in the X direction. The partition plate 44 is provided over an area that either coincides with the range of the length L1 and width W1 or is wider than the range of the length L1 and width W1.

[0039] Note that Figure 3 shows an example in which the position of the installation area on the upper surface 12 and the position of the installation area on the lower surface 13 are the same in the E direction, but the positions of the installation area on the upper surface 12 and the position of the installation area on the lower surface 13 do not have to be the same and may be different. This embodiment In the example shown, all the heating elements HS have the same shape (rectangular parallelepiped), but the individual heating elements HS may have different shapes, in which case the size of the installation area may also differ.

[0040] This embodimentIn the boiling portion 10, the partition plate 44 is provided across the entire storage space 11 (the entire length in the E direction and the entire width in the X direction). Therefore, the partition plate 44 completely divides the storage space 11 into an upper space 11a and a lower space 11b. Specifically, the storage space 11 has a length L in the E direction, a width W in the X direction (see FIG. 4), and a height H in the thickness direction of the boiling portion 10 (see FIG. 4). The partition plate 44 is formed within the range of the length L and width W, and is disposed at a position that divides the storage space 11 in the thickness direction into heights h1 and h2.

[0041] In a configuration in which the partition plate 44 separates the entire storage space 11, as shown in FIG. 3, the upper space 11a is in direct communication with the through-hole 12a, but the lower space 11b is separated from the through-hole 12a by the partition plate 44. Therefore, the partition plate 44 has a first communication passage 45 that penetrates the partition plate 44 and connects the upper space 11a to the lower space 11b in a region that vertically overlaps the through-hole 12a in the upper surface 12. The first communication passage 45 is a passage that transfers refrigerant gas 1a generated in the lower space 11b to the through-hole 12a, and a passage that transfers refrigerant liquid 1b returning from the condensation section 20 to the boiling section 10 to the lower space 11b. In the example shown in FIG. 3, the first communication passage 45 is a through-hole that penetrates the partition plate 44 in the thickness direction.

[0042] Also, This embodiment In the example of FIG. 3, a second communication passage 46 that connects the upper space 11a and the lower space 11b is formed at one end E1 located on the lower side of the accommodation space 11. Note that, as shown in FIG. 2, the one end E1 located on the lower side refers to the end that is located relatively lower in the Z direction of both ends of the boiling part 10 that extend diagonally downward (in the E direction). The other end E2 is located relatively higher in the Z direction. In the example of FIG. 3, the second communication passage 46 is a notch provided in one end of the partition plate 44.

[0043] The second communication passage 46 is provided at the one end E1, thereby allowing the refrigerant liquid 1b to move between the upper space 11a and the lower space 11b at the lowest point of the storage space 11. In the example shown in FIG. 2, the liquid level 1c of the refrigerant 1 is below the first communication passage 45 (at the upper end of the installation area of the top surface 12). In this case, the refrigerant liquid 1b stored in the upper space 11a and the refrigerant liquid 1b stored in the lower space 11b are separated by the partition plate 44. However, because the refrigerant liquid 1b can move between the upper space 11a and the lower space 11b via the second communication passage 46, the amount of stored liquid can be adjusted so that the liquid level in the upper space 11a and the liquid level in the lower space 11b are aligned.

[0044] Fig. 5 shows the planar shape of the first member 41 (boiling portion 10). An installation area having a length L1 and a width W1 is formed on the upper surface 12 of the boiling portion 10, and through-holes 12a having a length L2 are formed therein. In the example of Fig. 5, rectangular through-holes 12a extending in the X direction are formed within the length L2 range.

[0045] 6 shows the planar shape of the partition plate 44. The partition plate 44 has a through hole that forms the first communication passage 45 and a notch that forms the second communication passage 46. The partition plate 44 is formed continuously between the first communication passage 45 and the second communication passage 46 without interruption. The first communication passage 45 is formed by a through hole 44a. The through hole 44a has a rectangular shape. The second communication passage 46 has a rectangular shape extending in the X direction.

[0046] In the example of Fig. 6, a partition plate 44 is provided in a portion of the region overlapping with the through hole 12a (see dashed line) of the upper surface 12 in the thickness direction on one end E1 side. A first communication passage 45 is provided in a portion of the region overlapping with the through hole 12a in the thickness direction on the other end E2 side. In the example of Fig. 6, the partition plate 44 is provided in a region of the through hole 12a formed within the range of length L2, the length L4 of which is approximately half of the length of the through hole 12a on the one end E1 side. The first communication passage 45 (through hole 44a) is provided in a region of the through hole 12a, the length L3 of which is approximately half of the length of the through hole 12a on the other end E2 side.

[0047] Therefore, refrigerant liquid 1b returning from the condensation section 20 to the boiling section 10 after passing through approximately half of the through-hole 12a on the one end E1 side is received by the partition plate 44 and distributed to the upper space 11a. Refrigerant liquid 1b returning from the condensation section 20 to the boiling section 10 after passing through approximately half of the through-hole 12a on the other end E2 side passes through the first communication passage 45 and is distributed to the lower space 11b.

[0048] In this way, by forming the partition plate 44 on the one end E1 side of the region overlapping with the through hole 12a and forming the first communication passage 45 on the other end E2 side, it is possible to adjust the distribution ratio of the condensed refrigerant liquid 1b to the upper space 11a and the lower space 11b. Increasing the ratio of the region where the partition plate 44 is formed increases the distribution ratio of the refrigerant liquid 1b to the upper space 11a, and increasing the ratio of the region where the first communication passage 45 is formed increases the distribution ratio of the refrigerant liquid 1b to the lower space 11b. In the example of Figure 6, the partition plate 44 overlaps with approximately half of the through hole 12a, and the first communication passage 45 also overlaps with approximately half of the through hole 12a, so the distribution ratio of the refrigerant liquid 1b is the same (1:1). The ratio between the formation area of the partition plate 44 and the formation area of the first communication passage 45 (the ratio between length L4 and length L3 within the range of length L2) can be set, for example, according to the ratio between the heat generation amount of the heating element HS installed on the upper surface 12 and the heat generation amount of the heating element HS installed on the lower surface 13.

[0049] As shown in Fig. 4, the lower space 11b is partitioned by a bottom plate portion 42b of the second member 42, two side wall portions 42c on both sides in the X direction, and the lower surface of the partition plate 44. Furthermore, as shown in Fig. 7, the lower space 11b is partitioned into a plurality of refrigerant passages 42e by partition wall portions 42d extending in the E direction. In the example of Fig. 7, three partition wall portions 42d are provided, and the lower space 11b is partitioned into four refrigerant passages 42e. As shown in Fig. 4, the upper surfaces of the two side wall portions 42c on both sides in the X direction and the upper surfaces of the three partition wall portions 42d are in contact with the lower surface of the partition plate 44.

[0050] The through-hole 44a (see FIG. 6) constituting the first communication passage 45 is formed so as to straddle the positions where the four refrigerant passages 42e in the lower space 11b are formed. The width of the through-hole 44a in the X direction is approximately equal to the sum of the widths of the individual refrigerant passages 42e in the X direction.

[0051] As shown in FIG. 4, the first member 41 constituting the upper space 11a has a structure substantially identical to that of the second member 42, except for the through-hole 12a (see FIG. 5). The upper space 11a is partitioned by a top plate 41b of the first member 41, two side wall portions 41c on both sides in the X direction, and the upper surface of a partition plate 44. The upper space 11a is partitioned into multiple refrigerant passages 41e by partition wall portions 41d extending in the E direction. In the example shown in FIG. 4, three partition wall portions 41d are provided, and the upper space 11a is partitioned into four refrigerant passages 41e. The lower surfaces of the two side wall portions 41c on both sides in the X direction and the lower surfaces of the three partition wall portions 41d are in contact with the upper surface of the partition plate 44.

[0052] The length in the X direction of second communication passage 46 (see FIG. 6) cut out and formed in partition plate 44 is approximately equal to the distance between a pair of side wall portions 42c (a pair of side wall portions 41c) on both sides in the X direction shown in FIG. 7. In other words, second communication passage 46 is formed across four refrigerant passages 42e in lower space 11b and four refrigerant passages 41e in upper space 11a. As a result, second communication passage 46 is configured to mutually communicate the multiple (eight) passages provided in upper space 11a and lower space 11b.

[0053] As shown in Figure 4, the first member 41 and the second member 42 are joined together by a partition plate 44, forming an integrated unit. The partition plate 44 is made of a brazing sheet with a brazing material applied to both sides. The upper and lower surfaces of the partition plate 44 are flat. The boiling section 10 is formed by placing and brazing cover members 43 on one end E1 and the other end E2 of the assembly (case member 40) of the first member 41, the second member 42, and the partition plate 44.

[0054] (Cooler operation) The operation of the cooler 100 will be described. FIG. 8 is a schematic diagram of the boiling portion 10 of the cooler 100. When the heating element HS generates heat, the generated heat is absorbed by the refrigerant 1 in the boiling portion 10. The heat from the heating element HS located on the upper surface 12 is absorbed by the refrigerant 1 contained in the upper space 11a, and the heat from the heating element HS located on the lower surface 13 is absorbed by the refrigerant 1 contained in the lower space 11b. Because the boiling portion 10 is inclined downward at an angle θ and the liquid level 1c of the refrigerant 1 is located at the upper end of the installation area, the area of the internal upper surface 41a of the upper space 11a that overlaps with the installation area is always in contact with the refrigerant liquid 1b. This prevents the internal upper surface 41a from drying out and becoming covered with refrigerant gas 1a. In each of the upper space 11a and the lower space 11b, the refrigerant 1 absorbs heat and boils to vaporize into refrigerant gas 1a.

[0055] Refrigerant gas 1a generated in upper space 11a moves along inner upper surface 41a toward other end E2. Because inner upper surface 41a is inclined upward at angle θ toward other end E2, refrigerant gas 1a is prevented from stagnating on inner upper surface 41a without moving. When refrigerant gas 1a released from liquid level 1c reaches the position where through-hole 12a is formed, refrigerant gas 1a passes through through-hole 12a and moves into connecting portion 30.

[0056] Refrigerant gas 1a generated in lower space 11b moves upward within lower space 11b, comes into contact with the lower surface of partition plate 44, and moves along partition plate 44 toward other end E2. Partition plate 44 prevents refrigerant gas 1a generated in lower space 11b from moving upward to inner upper surface 41a of upper space 11a, thereby preventing excessive concentration of refrigerant gas 1a on inner upper surface 41a. When refrigerant gas 1a released from liquid level 1c reaches the position where first communication passage 45 is formed, refrigerant gas 1a passes through first communication passage 45 and moves into upper space 11a. Refrigerant gas 1a that has moved into upper space 11a continues to pass upward through upper space 11a and moves into connecting portion 30 through through-hole 12a.

[0057] Refrigerant gas 1a passes upward through connecting portion 30 and flows into accommodation space 21a of condenser portion 20 located above. In accommodation space 21a, refrigerant gas 1a moves upward while threading its way through gaps between fins 25 and diffusing.

[0058] As shown in Fig. 2, in the condensation section 20, heat exchange occurs between the refrigerant gas 1a in the storage space 21a and the external fluid 2 passing through the flow path 22 (see Fig. 1). Through the heat exchange, the refrigerant gas 1a releases heat of condensation to the external fluid 2 and condenses into refrigerant liquid 1b. The condensed refrigerant liquid 1b drops from the storage space 21a into the connection section 30 and passes through the through-hole 12a to return to the refrigerant liquid 1b stored in the boiling section 10.

[0059] ( This embodiment effect) This embodiment Then, the following effects can be obtained:

[0060] This embodiment As described above, the boiling portion 10 is provided so as to extend obliquely downward from the connection portion (connection portion 30) with the condensing portion 20. This allows the internal upper surface 41a of the storage space 11 for the refrigerant 1 to be inclined relative to the liquid level 1c of the refrigerant liquid 1b, thereby allowing the internal upper surface 41a of the storage space 11 to be continuously in contact with the refrigerant liquid 1b. Furthermore, since the storage space 11 is inclined upward toward the condensing portion 20, the refrigerant gas 1a vaporized inside the storage space 11 moves along the inclined storage space 11 toward the condensing portion 20. This prevents the refrigerant gas 1a from excessively accumulating on the internal upper surface 41a of the storage space 11. As a result, sufficient cooling performance can be achieved for the heating element HS installed on the upper surface 12 of the boiling portion 10. Therefore, by allowing the heating element HS to be installed not only on the lower surface 13 but also on the upper surface 12 of the boiling portion 10, the installation area for the heating element HS can be increased even in a horizontal boiling type cooler 100.

[0061] Also, This embodimentAs described above, the boiling section 10 is inclined at an inclination angle θ of 5 degrees or more and less than 45 degrees with respect to the horizontal direction, so that the advantage of the horizontal boiling type cooler 100 that the height dimension of the boiling type cooler 100 can be reduced is obtained, while the heating element HS can also be installed on the upper surface 12 of the boiling section 10, thereby obtaining a horizontal boiling type cooler 100 with an increased installation area for the heating element HS.

[0062] Also, This embodiment As described above, the boiling portion 10 further includes a partition plate 44 that divides the storage space 11 into an upper space 11a adjacent to the upper surface 12 and a lower space 11b adjacent to the lower surface 13, and the partition plate 44 can prevent the refrigerant gas 1a generated in the lower space 11b of the storage space 11 from moving to the upper space 11a. This prevents all of the refrigerant gas 1a from gathering on the inner upper surface 41a and preventing contact between the refrigerant liquid 1b and the inner upper surface 41a, thereby improving the cooling performance of the heating element HS on the upper surface 12 of the boiling portion 10. It is also known that in a heat exchanger, a state in which a liquid phase and a gas phase exist in an appropriate ratio improves cooling performance due to the evaporation of a liquid film along the heat transfer surface, rather than a state in which the heat transfer surface is completely filled with the liquid phase. Therefore, if the refrigerant gas 1a generated in the lower space 11b is blocked by the partition plate 44, and as a result the ratio of liquid phase to gas phase on the internal upper surface 41a of the upper space 11a is appropriate, further effective improvement in the cooling performance on the upper surface 12 can be expected.

[0063] Also, This embodiment As described above, partition plate 44 is provided in at least the range OA that overlaps in the thickness direction of boiling portion 10 with the installation area of heating element HS on upper surface 12, and therefore partition plate 44 can prevent refrigerant gas 1a generated in lower space 11b from collecting in the area of inner upper surface 41a of storage space 11 directly below heating element HS on upper surface 12 of boiling portion 10. Therefore, refrigerant gas 1a can be effectively prevented from collecting in the area of inner upper surface 41a where dryout is most likely to occur.

[0064] Also, This embodimentAs described above, the partition plate 44 is provided over the entire storage space 11, which reliably prevents the refrigerant gas 1a generated in the lower space 11b from collecting on the internal upper surface 41a of the storage space 11. Furthermore, the partition plate 44 has a first communication passage 45 that penetrates the partition plate 44 and connects the upper space 11a and the lower space 11b in an area that vertically overlaps with the through-hole 12a in the upper surface 12, so that the refrigerant gas 1a in the lower space 11b can pass through the first communication passage 45 and move toward the condenser 20. Therefore, there is no need to form a passage in the boiling portion 10 separate from the partition plate 44 for moving the refrigerant gas 1a in the lower space 11b to the condenser 20, which simplifies the structure of the boiling-type cooler.

[0065] Also, This embodiment As described above, the second communication passage 46 that connects the upper space 11a and the lower space 11b is formed at the one end E1 located on the lower side of the storage space 11, so even if the storage space 11 is partitioned into the upper space 11a and the lower space 11b, the refrigerant liquid 1b can be moved via the second communication passage 46. Therefore, the refrigerant liquid 1b is not unevenly stored in either the upper space 11a or the lower space 11b, and the amount of refrigerant liquid 1b stored can be made uniform between the upper space 11a and the lower space 11b. This embodiment In this case, the second communication passage 46 interconnects the four refrigerant passages 42e in the lower space 11b and the four refrigerant passages 41e in the upper space 11a, which also reduces variations in the amount of refrigerant liquid 1b stored among the individual refrigerant passages.

[0066] Also, This embodimentAs described above, the condensing section 20 is provided to extend upward from the upper surface 12 of the boiling section 10 and has the flow passage 22 for the external fluid 2 that penetrates the condensing section 20 in the horizontal direction. Therefore, even if the boiling section 10 is tilted diagonally downward, the external fluid 2 can be sent horizontally to the condensing section 20 extending in the vertical direction. Therefore, in a configuration in which the refrigerant gas 1a in the condensing section 20 is condensed by forced cooling in which the external fluid 2 is sent by the driving source (blower 3), it is not necessary to tilt the driving source or the flow passage for the external fluid 2 in accordance with the inclination of the boiling section 10. Therefore, when the boiling type cooler 100 is combined with an external device, the boiling type cooler 100 can be easily adapted to the external device.

[0067] [ Reference example ] Next, referring to FIGS. 9 to 11, Reference example The configuration of the boiling type cooler 200 (hereinafter referred to as the cooler 200) will be described. Reference example In this case, a partition plate 44 is provided in the accommodation space 11 of the boiling section 10. Memorial An example in which the partition plate 44 is not provided in the accommodation space 11 of the boiling part 10, unlike the embodiment, will be described.

[0068] In addition, Reference example So, up Memorial The same components as those in the embodiment will be designated by the same reference numerals and the description thereof will be omitted. Reference example 1. In the boiling section 10, the outer shape of the boiling section 10, the condensing section 20, and the connecting section 30 are the same as those shown in FIG. Memorial As shown in FIG. Reference example However, the boiling section 10 is provided so as to extend obliquely downward from the connection part (connection part 30) with the condensation section 20, and is inclined downward at an angle θ with respect to the horizontal direction (Y direction). Only the internal structure of the boiling section 10 will be described below.

[0069] As shown in Figure 9, Reference exampleIn the boiling portion 10, a partition plate 44 is not provided in the storage space 11 of the boiling portion 10. In other words, the storage space 11 is not divided into an upper space 11a and a lower space 11b, but is a continuous space as a whole. As shown in FIG. 10, the storage space 11 is divided by an inner upper surface 41a of the first member 41, an inner lower surface 42a of the second member 42, a side wall portion 41c of the first member 41 and a side wall portion 42c of the second member 42, a cover member 43 at one end E1 (see FIG. 9), and a cover member 43 at the other end E2 (see FIG. 9). Memorial As in the embodiment, the refrigerant passage is divided into four refrigerant passages by three partition walls 41 d, 42 d. Since no partition plate 44 is provided, each refrigerant passage is formed from the inner lower surface 42 a to the inner upper surface 41 a, and has a height equal to the height H of the storage space 11.

[0070] Reference example In the present embodiment, since the partition plate 44 is not provided, the case member 40 does not have to be composed of two members, the first member 41 and the second member 42. For example, the cylindrical case member 40, in which the first member 41 and the second member 42 are integrated, may be formed as a single member by extrusion molding.

[0071] Reference example Other configurations of Memorial It is the same as the embodiment.

[0072] (Cooler operation) As shown in Figure 11, Reference example But, above Memorial As in the embodiment, the boiling portion 10 is inclined downward at an angle θ, and the liquid level 1c of the refrigerant 1 is located at a height that is the upper end of the installation area. Therefore, the inner upper surface 41a of the upper space 11a is always in contact with the refrigerant liquid 1b.

[0073] Reference example In this case, the refrigerant gas 1a generated near the inner lower surface 42a of the accommodation space 11 by the heat of the heating element HS provided on the lower surface 13 moves toward the inner upper surface 41a without being blocked along the way. Reference exampleIn this case, both refrigerant gas 1a generated on the inner upper surface 41a side and refrigerant gas 1a generated on the inner lower surface 42a side move along inner upper surface 41a toward other end E2. Because inner upper surface 41a is inclined upward at angle θ toward other end E2, refrigerant gas 1a is prevented from accumulating without moving on inner upper surface 41a.

[0074] When the refrigerant gas 1a reaches the position where the through-hole 12a is formed, the refrigerant gas 1a passes through the through-hole 12a and moves into the connecting portion 30. Other operations of the cooler 100 are the same as those described above. Memorial It is the same as the embodiment.

[0075] ( Reference example effect) Reference example So, up Memorial As in the embodiment, the boiling portion 10 is provided so as to extend obliquely downward from the connection portion 30 with the condensing portion 20, so that the refrigerant liquid 1b can be continuously contacted with the inner upper surface 41a of the accommodation space 11, and the refrigerant gas 1a can be prevented from excessively accumulating on the inner upper surface 41a. As a result, sufficient cooling performance can be exhibited for the heating element HS placed on the upper surface 12 of the boiling portion 10, so that the heating element HS can be placed on not only the lower surface 13 but also the upper surface 12 of the boiling portion 10, thereby enabling the installation area of the heating element HS to be increased even in a horizontal boiling type cooler 100.

[0076] Reference example Other effects of Memorial It is the same as the embodiment.

[0077] [Example] next, The above The cooler 100 of the embodiment and Reference example The results of an experiment conducted to confirm the effect of the cooler 200 will be described.

[0078] (Boiling section structure) In the example, The above The cooler 100 of the embodiment, Reference exampleThe cooling performance of each of the coolers 200 was measured under the same operating conditions. The above ) and without the partition plate 44 ( Reference example The cooling performance was measured in two types of boiling areas:

[0079] (tilt angle) The cooling performance was measured under several conditions for the angle θ of the boiling portion 10. Specifically, the measurements were performed under three conditions: θ=5 degrees, θ=10 degrees, and θ=0 degrees (horizontal) as shown in FIG.

[0080] (Operating conditions) Additionally, assuming that the heat generation amount of the heating element HS changes during actual operation, measurements were taken under multiple heat generation conditions. Specifically, the heat generation amount during assumed rated operation of the heating element HS, which is made up of a power module, was set to 100%, and measurements were taken under three conditions: 50%, 100%, and 150%.

[0081] Therefore, for two types of structures, with and without a partition plate, cooling performance was measured under three operating conditions of 50%, 100%, and 150% for six configurations combining three inclination angles θ = 10 degrees, 5 degrees, and 0 degrees (0 degrees is the comparative example).

[0082] 13 to 15 are graphs showing the results of measuring cooling performance. FIGS. 13 to 15 show the results of measurements under heat generation conditions of 50%, 100%, and 150%, respectively. The horizontal axis of each graph in FIGS. 13 to 15 indicates the temperature measurement position. The temperature measurement positions indicate six measurement positions set at intervals along the E direction in the installation area of the heating element HS in the boiling section 10. Within the installation area, measurement position 1 is closest to one end E1, and measurement position 6 is closest to the other end E2. The vertical axis of each graph indicates the difference ΔT [K] between the mounting surface temperature of the heating element HS and the internal refrigerant temperature at each temperature measurement position. Because the heating element HS is installed on both the upper surface 12 and the lower surface 13, measurements on both the upper surface 12 and the lower surface 13 are obtained for the same temperature measurement position. The smaller the difference value ΔT, the higher the cooling performance, and the smaller the variation in the difference value ΔT at each temperature measurement position, the less localized performance fluctuations there are (the more stable the cooling performance). Each graph shows a reference line (thick line) that indicates the design value (theoretical value) of the difference value ΔT, calculated from the specifications of the boiling section 10 and the set value of the heat generation amount of the heating element HS, without taking into account the behavior of the refrigerant gas 1a, as a guide for evaluating cooling performance. The value of the reference line varies depending on the heat generation amount conditions (50%, 100%, 150%).

[0083] Figure 16 shows a graph that compiles the graphs in Figures 13 to 15. The vertical axis in Figure 16 is the difference value ΔT [K], the same as in Figures 13 to 15. The horizontal axis represents the experimental conditions, showing the values for the top and bottom surfaces for six configurations that combine the presence or absence of a partition plate and the inclination angle θ. In Figure 16, the measurement results for a 50% heat generation rate (see Figure 13), a 100% heat generation rate (see Figure 14), and a 150% heat generation rate (see Figure 15) are each shown with different hatching. Each measurement result is shown as a bar graph showing the range between the maximum and minimum values of ΔT at six temperature measurement locations. The lower the position of the plotted bar, the lower the value of ΔT, and the shorter the bar, the smaller the difference between the maximum and minimum values of ΔT.

[0084] (Comparison of tilt angles) The effect of the tilt angle on cooling performance will be examined with reference to Figures 13 to 15. Plots A1, A2, and A3 represent the measurement results for the upper surface 12 of the boiling portion 10 with a partition plate, where θ = 10 degrees, 5 degrees, and 0 degrees. Plots A1 and A2, where the boiling portion 10 is tilted, are located lower than plot A3, which is a comparative example. Furthermore, plots A1 and A2 have smaller variations in ΔT than plot A3.

[0085] Plots A4, A5, and A6 represent the measurement results for θ = 10 degrees, 5 degrees, and 0 degrees for the lower surface 13 of the boiling section 10 with the partition plate. The measurement results for the lower surface 13 do not differ as greatly as the measurement results for the upper surface 12 (A1 to A3).

[0086] Plots B1, B2, and B3 represent the measurement results for the upper surface 12 of the boiling portion 10 without a partition plate, with θ = 10 degrees, 5 degrees, and 0 degrees. Plots B1 and B2, where the boiling portion 10 is tilted, are located lower than plot B3, which is a comparative example. Furthermore, plots B1 and B2 have smaller variations in ΔT than plot B3.

[0087] Plots B4, B5, and B6 represent the measurement results for θ = 10 degrees, 5 degrees, and 0 degrees for the lower surface 13 of the boiling section 10 with the partition plate. The measurement results for the lower surface 13 do not differ as greatly as the measurement results for the upper surface 12 (B1 to B3).

[0088] Focusing on the measurement results of the upper surface 12, the measurement results (A1, A2, B1, B2) for θ=10 degrees and θ=5 degrees consistently have ΔT values near the reference line in Figures 13 to 15. In contrast, the measurement results for the comparative example at θ=0 degrees (A3, B3) have ΔT values above the reference line in Figures 13 to 15, and there is a large deviation from the measurement results (A1, A2, B1, B2) for θ=10 degrees and θ=5 degrees. The measurement results (A1, A2, B1, B2) for θ=10 degrees and θ=5 degrees on the upper surface 12 have ΔT values that are equal to or smaller than the measurement results (A4, A5, B4, B5) for θ=10 degrees and θ=5 degrees on the lower surface 13.

[0089] From this, The above Embodiments and Reference example As shown above, it has been confirmed that by tilting the boiling portion 10 diagonally downward from the horizontal direction, the cooling performance on the upper surface 12 is improved, and that the cooling performance on the upper surface 12 is equal to or greater than that on the lower surface 13.

[0090] Furthermore, in Figure 15, which shows a condition where the amount of heat generated is large, the ΔT value for the measurement results (A2, B2) at θ = 5 degrees is large, and the ΔT variation between each temperature measurement position is large. In contrast, the measurement results (A1, B1) at θ = 10 degrees show that the ΔT value is below the reference line at every temperature measurement position, indicating small variation. This tendency is not seen at 50% heat generation (Figure 13) or 100% heat generation (Figure 14). This confirms that increasing the tilt angle θ is effective in maintaining cooling performance (expanding the allowable range of heat generation), especially under high-load conditions where heat generation is large.

[0091] (Comparison with and without divider) Next, we consider the effect of the presence or absence of a partition on cooling performance. When θ=10 degrees and the case with a partition (A1) on the top surface 12 is compared with the case without a partition (B1), the case with the partition has the same or smaller ΔT value.

[0092] When comparing the case where the partition plate is provided (A2) with the case where the partition plate is not provided (B2) on the top surface 12 at θ=5 degrees, the value of ΔT is smaller with the partition plate. In particular, under high load conditions with a heat generation rate of 150%, the value of ΔT is significantly reduced by providing the partition plate 44. In this way, it was confirmed that providing the partition plate 44 can improve cooling performance (reduce the value of ΔT). Furthermore, from the results of the study on the inclination angle θ, it was confirmed that cooling performance under high load conditions can be significantly improved by increasing the inclination angle θ, but it was also confirmed that providing the partition plate 44 can improve cooling performance when the angle θ cannot be made sufficiently large.

[0093] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and includes all modifications (variations) within the meaning and scope of the claims.

[0094] For example, the above Embodiment Although the example in which the heating element HS is a power module used in a power conversion device has been shown, the present invention is not limited to this. In the present invention, the heating element may be any object. The heating element may be a semiconductor chip such as a CPU or an electronic circuit mounted on an electronic device such as a server.

[0095] Also, the above Embodiment In the example described above, the condenser section 20 is provided to extend upward from the upper surface 12 of the boiling section 10, and has the flow passage 22 for the external fluid 2 that passes through the condenser section 20 in the horizontal direction, but the present invention is not limited to this. In the present invention, the condenser section 20 may be provided to extend in a direction other than upward, and the flow passage 22 for the external fluid 2 may be provided to pass through the condenser section 20 in a direction other than the horizontal direction.

[0096] 17 , for example, the condenser section 20 is provided so as to protrude horizontally (Y direction) relative to the connection section 30 that rises upward from the boiling section 10. A flow path 22 for the external fluid 2 is provided so as to penetrate the condenser section 20 in the up-down direction (Z direction). The external fluid 2 passes upward through the flow path 22 by, for example, a blower 3 arranged below the condenser section 20. Conversely, the external fluid 2 may pass downward through the flow path 22 by a blower arranged above the condenser section 20.

[0097] Also, the above EmbodimentAlthough an example in which a connecting portion 30 is provided to connect the condenser portion 20 and the boiling portion 10 has been described above, the present invention is not limited to this. In the present invention, the condenser portion 20 may be directly connected to the upper surface 12 of the boiling portion 10. In other words, a configuration may be adopted in which the lower end of the storage space 21a of the condenser portion 20 communicates with the through-hole 12a in the upper surface 12 of the boiling portion 10, and the wall portion 24 of the condenser portion 20 is joined to the upper surface 12 of the boiling portion 10 so that the storage space 21a and the storage space 11 form a closed space.

[0098] Also, the above Embodiment Although an example has been shown in which the boiling section 10 and the condensing section 20 are connected by a single passage (connecting section 30), the present invention is not limited to this. In the present invention, for example, a first passage through which refrigerant gas 1a moving to condensing section 20 passes and a second passage through which refrigerant liquid 1b moving to boiling section 10 passes may be provided, thereby forming a circulation path for refrigerant 1 in a loop shape.

[0099] Also, the above Embodiment Although examples where the angle θ of the boiling portion 10 is 5 degrees and 10 degrees have been shown above, the present invention is not limited to these. The angle θ may be an angle of 5 degrees or more and less than 10 degrees, or may be an angle greater than 10 degrees. For example, the example shown in Fig. 18 shows an example where θ = 30 degrees.

[0100] Also, the above Embodiment In the example shown in FIG. 18, the installation area on the upper surface 12 of the boiling portion 10 and the installation area on the lower surface 13 are located at the same position and in the same range (within the range of length L1) in the E direction, but the present invention is not limited to this. The installation area on the upper surface 12 and the installation area on the lower surface 13 may be located at different positions and in different ranges. For example, in the example shown in FIG. 18, two installation areas are located on the upper surface 12 of the boiling portion 10, and three installation areas are located on the lower surface 13. In particular, the installation area on the other end E2 side of the lower surface 13 is located in a position aligned with the condenser portion 20 in the Z direction. With the configuration of this modified example, more heating elements HS can be installed.

[0101] Also, the above EmbodimentIn the example shown above, when the cooler is not operating, the liquid level 1c of the refrigerant 1 is set within the installation area of the heating element HS on the upper surface 12 of the boiling portion 10, but the present invention is not limited to this. In the present invention, the liquid level 1c may be set at a position above the installation area of the heating element HS on the upper surface 12. With this configuration, the entire area of the inner upper surface 41a of the accommodation space 11 that faces the installation area of the heating element HS (the area directly below the heating element HS) can be brought into contact with the refrigerant liquid 1b.

[0102] Also, above Memorial In the embodiment, the partition plate 44 is provided throughout the entire storage space 11, but the present invention is not limited to this. In the present invention, the partition plate 44 may be provided locally in a part of the storage space 11. For example, in the example shown in Fig. 19, the partition plate 44 is provided in an area OA that overlaps the installation area of the heating element HS on the upper surface 12 in the thickness direction of the boiling portion 10, and is not provided in other areas. Even in this case, the partition plate 44 can prevent the refrigerant gas 1a from the lower space 11b from collecting on the inner upper surface 41a directly below the installation area of the heating element HS on the upper surface 12.

[0103] Also, above Memorial In the embodiment, the height h1 of the upper space 11a and the height h2 of the lower space 11b are equal to each other, but the present invention is not limited to this. In the present invention, the height h1 of the upper space 11a and the height h2 of the lower space 11b may be different. For example, the height h1 of the upper space 11a and the height h2 of the lower space 11b may be set depending on the heat generation amount of the heat generating element HS installed on the upper surface 12 and the heat generation amount of the heat generating element HS installed on the lower surface 13.

[0104] Also, above MemorialIn the embodiment, the partition plate 44 is formed with only the first communication passage 45 formed by a through-hole and the second communication passage 46 formed by a notch, and no through-holes or notches are formed in other portions. However, the present invention is not limited to this. In the present invention, the partition plate 44 may be formed with through-holes or notches to adjust the amount of refrigerant gas 1a passing through. For example, in the example shown in FIG. 20 , the partition plate 44 is formed with a plurality of through-holes 441. The through-holes 441 are formed in an area that overlaps the installation area of the heating element HS on the upper surface 12 in the thickness direction of the boiling portion 10. The through-holes 441 are configured to allow a portion of the refrigerant gas 1a generated in the lower space 11b to pass to the upper space 11a. The through-holes 441 are formed with a size that ensures an appropriate amount of refrigerant gas 1a passes through the through-holes 441. This allows the ratio of the amount of refrigerant liquid 1b to the amount of refrigerant gas 1a on the inner upper surface 41a to be adjusted, and under conditions where the refrigerant liquid 1b and refrigerant gas 1a are present in an appropriate ratio, the cooling performance on the upper surface 12 side can be effectively improved.

[0105] Also, above Memorial In the embodiment, the first communication passage 45 is formed by a through hole formed in the partition plate 44, but the present invention is not limited to this. For example, when the partition plate 44 is partially provided within the accommodation space 11 as shown in FIG. 19 , the upper space 11a and the lower space 11b communicate with each other in the area where the partition plate 44 is not provided, and therefore the first communication passage 45 does not need to be provided. Furthermore, when the partition plate 44 is provided over the entire accommodation space 11, the first communication passage 45 may be formed by a notch formed in the other end of the partition plate 44, similar to the second communication passage 46. Furthermore, for example, as shown in FIG. 21 , a recess 43a spanning the upper space 11a and the lower space 11b may be formed in the cover member 43 that closes the other end E2 of the boiling portion 10, and the first communication passage 45 may be formed by this recess 43a.

[0106] Also, above MemorialIn the embodiment, an example has been shown in which the second communication passage 46 is provided as a notch formed in the partition plate 44, but the present invention is not limited to this. For example, the second communication passage 46 may be configured as a through-hole formed in the partition plate 44, similar to the first communication passage 45. Also, as shown in FIG. 21 , for example, a recess 43b spanning the upper space 11a and the lower space 11b may be formed in the cover member 43 that closes one end E1 of the boiling section 10, and the recess 43b may configure the second communication passage 46. Also, in the present invention, the second communication passage 46 does not necessarily have to be provided.

[0107] Also, above Memorial In this embodiment, an example is shown in which the upper space 11a and the lower space 11b are each divided into a plurality of (four) refrigerant passages 41e and 42e by partition walls 41d and 42d. did However, the present invention is not limited to this. In the present invention, the accommodation space 11 (upper space 11a and lower space 11b) does not have to be divided into a plurality of refrigerant passages. [Explanation of symbols]

[0108] 1 Refrigerant 1a Refrigerant gas 1b Refrigerant liquid 1c, 1d liquid level 2. External fluid 10 Boiling part 11 Containment Space 11a Upper space 11b Lower space 12 Top side 12a Through hole 13 Bottom side 20 Condenser 22 Distribution path 30 Connection 44 Divider 45 1st communication passage 46 2nd communication passage 100, 200 cooler (boiling type cooler) E1 One end E2 Other end HS heating element θ Tilt angle

Claims

1. a boiling portion having a storage space for storing a refrigerant and boiling the refrigerant by heat exchange with a heating element; a condensing section that is in communication with the boiling section and that condenses the refrigerant gas from the boiling section by heat exchange with an external fluid, the boiling portion is formed in a plate-like shape having an upper surface and a lower surface on which the heating element is installed, and is provided so as to extend obliquely downward from a connection portion with the condensing portion, and further includes a partition plate that divides the storage space into an upper space adjacent to the upper surface and a lower space adjacent to the lower surface, the condensation section is provided to extend upward from the upper surface of the boiling section, a through-hole that communicates the storage space with the condenser portion is formed on the upper surface of the boiling portion; the through-hole is configured to allow the refrigerant gas to flow into the condenser portion and allow the condensed refrigerant to flow into the accommodation space, The partition plate is provided across the entire storage space, and in a region that overlaps vertically with the through hole on the upper surface, has a first communication passage that passes through the partition plate to connect the upper space and the lower space.

2. 2. The boiling type cooler according to claim 1, wherein the boiling portion is inclined so that the liquid level of the refrigerant is located within an area on the upper surface where the heat generating element is installed or above the area where the heat generating element is installed.

3. The boiling type cooler according to claim 2 , wherein the boiling portion is inclined at an angle of 5 degrees or more and less than 45 degrees with respect to the horizontal direction.

4. 2. The boiling type cooler according to claim 1, wherein a second communication passage that connects the upper space and the lower space is formed at one end of the accommodation space located on the lower side.

5. The boiling type cooler according to claim 1 , wherein the condenser section has a flow passage for the external fluid that passes through the condenser section in a horizontal direction.

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