Cooling device and electronic device

Abstract

A cooling device (1) comprises a base plate (11) and at least one vapor chamber (12). At least one recess is formed in a first main surface (11a) of the base plate (11). At least one through hole that extends from the bottom surface of the recess to a second main surface (11b) is formed. The vapor chamber (12) has a base part (13) that is accommodated in the recess and a pipe part (14) that has at least one pipe (14a), which extends from the base part (13) and which is inserted through the through hole. The vapor chamber radiates, to the surrounding air via the base part (13) and the pipe part (14), heat which is transmitted from a heat-emitting body that is attached to the first main surface (11a) in a state of surface contact with the base part (13).

Description

Cooling and Electronic Equipment

[0001] The present disclosure relates to a cooling device and an electronic device.

[0002] Some electronic devices have a cooling device thermally connected to a heat-generating electronic component to prevent damage to the electronic component due to heat generated when power is applied. The cooling device cools the electronic component by dissipating heat transferred from the electronic component into the surrounding air. An example of this type of cooling device is disclosed in Patent Document 1. The tower-type heat sink disclosed in Patent Document 1 includes a heat pipe that is inserted from the bottom of a base, penetrates the base, and contacts a heat-generating CPU (Central Processing Unit), and a plurality of fins attached to the heat pipe.

[0003] Japanese Patent Application Laid-Open No. 2004-071635

[0004] The heat pipes of the tower-type heat sink disclosed in Patent Document 1 are U-shaped, so the bent portions do not contact either the base or the heat-generating body. In other words, in the tower-type heat sink disclosed in Patent Document 1, heat from the CPU is directly transferred only to the straight pipe portion of the heat sink that is in contact with the CPU. Increasing the capacity of the power conversion device increases the amount of heat generated by the switching elements, so it is necessary to improve the cooling performance of the cooling device.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a cooling device and electronic device having high cooling performance.

[0006] To achieve the above object, the cooling device of the present disclosure includes a base plate and at least one vapor chamber. At least one recess is formed in a first main surface of the base plate, and at least one through-hole is formed extending from the bottom of the recess toward a second main surface opposite the first main surface. The vapor chamber includes a base portion having a first cavity therein and accommodated in the recess; a pipe portion having a second cavity therein communicating with the first cavity and having at least one pipe extending from the base portion and inserted into the through-hole; and a coolant sealed in the first cavity and the second cavity. The vapor chamber dissipates heat transferred from a heating element attached to the first main surface in surface contact with the base portion to the surrounding air via the base portion and the pipe portion.

[0007] The cooling device according to the present disclosure includes a vapor chamber having a base portion housed in a recess formed in a base plate and a pipe portion extending from the base portion. The vapor chamber dissipates heat transferred from a heat generating element attached to the base plate in surface contact with the base portion into the surrounding air, resulting in a cooling device with high cooling performance.

[0008] 5 is a perspective view of a cooling device according to a first embodiment; a perspective view of a base plate according to a first embodiment; a perspective view of a vapor chamber according to a first embodiment; a front view of a cooling device according to a first embodiment; a diagram showing an example of attachment of an electronic component to a cooling device according to a first embodiment; a cross-sectional view of a cooling device according to a first embodiment taken along line VI-VI in FIG. 5; a cross-sectional view of an electronic device according to a first embodiment; a perspective view of a cooling device according to a second embodiment; a perspective view of a base plate according to a second embodiment; a front view of a second embodiment; a rear view of a third embodiment;

[0009] Hereinafter, a cooling device and an electronic device according to an embodiment of the present disclosure will be described in detail with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0010] First Embodiment An electronic device according to a first embodiment and a cooling device for cooling a heat generating element included in the electronic device will be described using a power conversion device mounted on a railway vehicle as an example.

[0011] The cooling device 1 shown in FIG. 1 includes a base plate 11 to which a heat generating element is attached, and a vapor chamber 12 that dissipates heat transferred from the heat generating element into the surrounding air.

[0012] As shown in FIG. 2 , at least one recess 11c, for example, nine recesses 11c, are formed in the first main surface 11a of the base plate 11. The recess 11c has a shape recessed in a direction perpendicular to the first main surface 11a. As an example, the recesses 11c are arranged two-dimensionally. The base plate 11 has at least one through hole 11d, for example, nine through holes 11d, extending from the bottom surface of the recess 11c toward the second main surface 11b opposite the first main surface 11a. As an example, one through hole 11d is formed in each recess 11c. The base plate 11 is preferably formed of a heat-conductive material, for example, a metal such as copper, aluminum, or iron.

[0013] 1 and 2, the X-axis and Z-axis are defined as axes included in the first main surface 11a and perpendicular to each other. The Y-axis is defined as an axis parallel to the penetration direction of the through-hole 11d penetrating the base plate 11 and perpendicular to the X-axis and Z-axis. As an example, the X-axis and Z-axis extend parallel to different side surfaces of the base plate 11. The side surfaces are surfaces continuous with the first main surface 11a and the second main surface 11b. This also applies to subsequent figures.

[0014] 1 and 3 , the vapor chamber 12 includes a base portion 13 accommodated in the recess 11c and a pipe portion 14 having at least one (e.g., four) pipes 14a extending from the base portion 13 and inserted into the through-hole 11d. The base portion 13 and the pipe portion 14 are integrally formed. As an example, each pipe 14a is attached to the base portion 13 by brazing. The vapor chamber 12, in contact with the base portion 13, dissipates heat transferred from a heating element attached to the first main surface 11a of the base plate 11 into the surrounding air via the base portion 13 and the pipe portion 14. The vapor chamber 12 is preferably formed of a heat-conductive material, such as a metal such as copper, aluminum, or iron.

[0015] As shown in Fig. 4, the base portions 13 of the vapor chambers 12 are spaced apart from one another. As shown in Fig. 5 and Fig. 6, which is a cross-sectional view taken along line VI-VI in Fig. 5, the electronic component 21, which is a heating element, is attached to the first main surface 11a of the base plate 11, for example, by a fastening member (not shown), in surface contact with the base portion 13. The electronic component 21 is preferably attached to the first main surface 11a with a casing 22 having, for example, a switching element therein in surface contact with the base portion 13. In other words, it is preferable that the surface of the casing 22 facing the base portion 13 and the end surface 13a of the base portion 13 facing the electronic component 21 abut against each other.

[0016] As shown in Fig. 6, the base portion 13 is preferably accommodated in the recess 11c in a state of surface contact with the bottom surface of the recess 11c. Specifically, the end surface 13c of the base portion 13 facing the pipe portion 14 is preferably accommodated in the recess 11c in a state of surface contact with the bottom surface of the recess 11c, specifically, the periphery of the through-hole 11d on the surface of the recess 11c facing in the negative Y-axis direction. As an example, the base portion 13 has a flat plate shape, and the bottom surface of the recess 11c is flat, so that the base portion 13 is accommodated in the recess 11c in a state of surface contact with the bottom surface of the recess 11c. In other words, the bottom surface of the recess 11c and the end surface 13c of the base portion 13 abut against each other.

[0017] The base portion 13 is attached to the base plate 11 by any method such as soldering, friction stir welding, or bonding with an adhesive. As an example, an end surface 13 a of the base portion 13 that abuts against the electronic component 21 is located on the same plane as the first main surface 11 a of the base plate 11.

[0018] The pipe 14a of the pipe portion 14 extends in a direction perpendicular to the first main surface, in other words, in a direction tilted from the Y-axis direction, and away from the base plate 11. As an example, the pipe 14a extends in the positive Y-axis direction and the positive Z-axis direction.

[0019] As shown in FIG. 6 , the base 13 has a first cavity 13b therein. The pipe 14a has a second cavity 14b therein that is connected to the first cavity 13b. The cooling device 1 includes a refrigerant 15 sealed in the first cavity 13b and the second cavity 14b. The refrigerant 15 exists in a gas-liquid two-phase state at room temperature. The refrigerant 15 is, for example, water. To promote circulation of the refrigerant 15, the first cavity 13b and the second cavity 14b are preferably provided with a member having a structure that causes capillary action, such as a wick or sintered copper powder.

[0020] 7 , the cooling device 1 is attached to the housing 31 of the electronic device 101 including the electronic component 21. Specifically, the cooling device 1 is attached to the housing 31 at a position where the base plate 11 covers the opening 31 a formed in the housing 31.

[0021] To improve the waterproofing performance of the electronic device 101, the cooling device 1 preferably includes a sealing member 16 that abuts against the base portion 13 and the base plate 11 in the through-hole 11d of the base plate 11. The sealing member 16 is applied to the inside of the through-hole 11d from the positive Y-axis direction after the vapor chamber 12 is attached to the base plate 11, for example. The sealing member 16 is, for example, a caulking agent.

[0022] Preferably, the cooling device 1 further includes a plurality of fins 17 attached to the pipe portion 14 to enhance cooling performance. The cooling device 1 is attached, for example, under the floor of the railway vehicle with the Y-axis direction coinciding with the width direction of the railway vehicle and the X-axis direction coinciding with the direction of travel of the railway vehicle. In this case, the cooling air, specifically the running air generated when the railway vehicle is moving, flows in the X-axis direction. In other words, the flow direction of the cooling air passing between the pipes 14a is the X-axis direction. The fins 17 are preferably formed from a heat-conductive material, for example, a metal such as copper, aluminum, or iron.

[0023] The mechanism by which the cooling device 1 having the above configuration cools the electronic component 21 will now be described. When the electronic component 21 generates heat while power is applied, the heat is transferred from the electronic component 21 to the refrigerant 15 via the base 13. As a result, the temperature of the refrigerant 15 rises, and a portion of the refrigerant 15 vaporizes. The vaporized refrigerant 15 flows into the pipe 14a and moves further inside the pipe 14a toward the tip of the pipe 14a, specifically, toward the end of the pipe 14a on the positive side of the Y axis.

[0024] While traveling through the pipe 14a, the refrigerant 15 transfers heat to the air surrounding the cooling device 1 via the pipe 14a and the fins 17. As a result, the temperature of the refrigerant 15 drops, and the refrigerant 15 liquefies. The liquefied refrigerant 15 returns to the base 13 by capillary action through gaps in the wick, sintered copper powder, and the like provided inside the pipe 14a. When the liquefied refrigerant 15 receives heat from the electronic components 21 via the base 13, it vaporizes again, flows into the pipe 14a, and moves inside the pipe 14a toward the tip of the pipe 14a. As the refrigerant 15 circulates, repeatedly vaporizing and liquefying as described above, heat generated in the electronic components 21 is dissipated into the air surrounding the cooling device 1, specifically, the air surrounding the pipe 14a and the fins 17, thereby cooling the electronic components 21.

[0025] As described above, the base portion 13 of the vapor chamber 12 is accommodated in the recess 11c of the base plate 11 included in the cooling device 1 according to the first embodiment. The vapor chamber 12 dissipates heat transferred from the electronic component 21 attached to the first main surface 11a of the base plate 11 while in surface contact with the base portion 13 to the surrounding air via the base portion 13 and the pipe portion 14. Because the electronic component 21 is in surface contact with the base portion 13, the cooling device 1 receives heat from the electronic component 21 more efficiently than a heat sink having a U-shaped heat pipe in which only the straight pipe portion receives heat directly from a heat generating element. Therefore, the cooling performance of the cooling device 1 is higher than that of a heat sink having a U-shaped heat pipe in which only the straight pipe portion receives heat directly from a heat generating element. Furthermore, even if the refrigerant 15 freezes in a low-temperature environment, the cooling device 1 can transfer heat to the frozen refrigerant 15 and melt it more quickly than a heat sink having the U-shaped heat pipe.

[0026] (Embodiment 2) The vapor chamber 12 may have any shape as long as it can radiate heat transferred from the electronic component 21 in surface contact to the surrounding air. A cooling device including a vapor chamber 12 having a structure different from that of Embodiment 1 will be described in Embodiment 2, focusing on the differences from Embodiment 1.

[0027] 8 includes a vapor chamber 12 having a base 13 on which a plurality of electronic components 21 are attached, the electronic components 21 being arranged in the direction of the cooling airflow passing through the pipes 14a, i.e., the X-axis direction. The electronic components 21 are attached to the cooling device 2 in the same manner as in the first embodiment. In other words, three electronic components 21 are attached to one base 13.

[0028] The electronic device 101 is, for example, a power conversion device that converts input power into power to be supplied to a load device and supplies the converted power to the load device. The electronic components 21 are, for example, switching elements included in the power conversion device. The electronic components 21 provided in surface contact with the same base portion 13 are switching elements that correspond to the same phase of AC power input to or output from a power conversion circuit provided in the power conversion device and are electrically connected in parallel. The switching elements that correspond to the same phase and are electrically connected in parallel are switched on and off at the same timing. Therefore, multiple electronic components 21 provided in surface contact with the same base portion 13 generate heat at the same timing.

[0029] 9 , three recesses 11c are formed in the base plate 11 of the cooling device 2, and one through-hole 11d is formed in each recess 11c. A pipe 14 of one vapor chamber 12 is inserted into each through-hole 11d. The three electronic components 21 are attached to the first main surface 11a of the base plate 11 in a state where the electronic components 21 are in surface contact with the base portion 13 of each vapor chamber 12.

[0030] As described above, the vapor chamber 12 included in the cooling device 2 according to the second embodiment dissipates heat transferred from electronic components 21 adjacent in the X-axis direction and mounted in surface-to-surface contact with the same base portion 13 to the surrounding air via the base portion 13 and the pipe portion 14. The multiple electronic components 21 mounted in surface-to-surface contact with the same base portion 13 are uniformly heated by the base portion 13. Electrical resistance varies with temperature, but uniform heating among the electronic components 21 mounted in surface-to-surface contact with the same base portion 13 reduces differences in resistance values. As a result, differences in current values ​​flowing through the electronic components 21, which are switching elements electrically connected in parallel and correspond to the same phase of AC power input to or output from the power conversion circuit of the power conversion device, are reduced. This reduces overcurrents caused by increased current in some electronic components 21 and shortens the lifespan of semiconductor elements.

[0031] The present disclosure is not limited to the above-described embodiment. The number, arrangement, and shape of the vapor chambers 12 are arbitrary as long as they can dissipate heat transferred from the electronic components 21 to the surrounding air. As an example, as shown in FIG. 10 , the multiple base portions 13 of the cooling device 3 are housed in abutting contact with each other in multiple recesses 11c adjacent to each other in the direction of the cooling air passing between the pipes 14a, i.e., in the X-axis direction, and are in surface contact with multiple electronic components 21 (not shown) that are electrically connected in parallel to each other.

[0032] The electronic components 21 are provided in surface contact with the bases 13, which are abutted against each other and housed in the recess 11c, and are uniformly heated by the bases 13, reducing the difference in resistance values ​​among the electronic components 21. As a result, for example, the difference in current values ​​flowing through the electronic components 21, which are switching elements electrically connected in parallel and correspond to the same phase of AC power input to or output from a power conversion circuit of the power conversion device, is reduced. This reduces the occurrence of overcurrent due to an increase in current through some of the electronic components 21, shortening the lifespan of semiconductor elements, and the like.

[0033] The shape of the base plate 11 is not limited to a plate-like shape, and can be any shape as long as it allows electronic components 21 to be attached to the first main surface 11a and allows the vapor chamber 12 to be accommodated in the recess 11c.

[0034] The shape of the pipe portion 14 may be any shape as long as it can dissipate heat transferred from the electronic component 21 via the base portion 13. As an example, the pipe 14a shown in Fig. 10 may extend in a direction perpendicular to the first main surface, i.e., in the positive direction of the Y axis.

[0035] The shape of the recess 11c formed in the base plate 11 may be any shape as long as the vapor chamber 12 can be in surface contact with the bottom surface. As an example, as shown in FIG. 11 , the vapor chamber 12 may be formed with a recess 11c in which a plurality of through holes 11d are formed. More specifically, each recess 11c has a plurality of through holes 11d aligned in the X-axis direction. As in the first embodiment, the pipe portion 14 of the vapor chamber 12 is inserted into each through hole 11d.

[0036] The electronic component 21 is not limited to a switching element, but may be any electronic component such as a thyristor or a diode that is housed inside the housing 31 and generates heat.

[0037] The electronic device 101 is not limited to a power conversion device, but may be any electronic device that houses a heat generating element inside the housing 31. Furthermore, the method of attaching the cooling device 1 to the housing 31 of the electronic device 101 is not limited to the above example. As an example, the cooling device 1 may be attached to the housing 31 in an orientation where the base plate 11 covers the opening 31 a from inside the housing 31.

[0038] The installation position of electronic device 101 is not limited to under the floor of the railcar, but may also be on the roof of the railcar. In this case, electronic device 101 is attached to the roof of the railcar with the X-axis direction coinciding with the width direction of the railcar and the Z-axis direction coinciding with the direction of travel of the railcar. Electronic device 101 is not limited to a railcar, and may be mounted on any moving object that generates wind when the railcar is running, such as a trolleybus or a tram. Electronic device 101 may also be installed outdoors or indoors.

[0039] The end surface 13a of the base portion 13 that abuts against the electronic component 21 does not have to be flush with the first main surface 11a of the base plate 11. As an example, the end surface 13a may be located on the negative Y-axis direction side of the first main surface 11a.

[0040] To achieve uniform temperature distribution between adjacent base portions 13, the cooling device 1 may further include, as shown in FIG. 12 , a heat transfer member 18 that extends in the direction of cooling airflow passing between the pipes 14a and transfers heat in the direction of extension. The heat transfer member 18 is, for example, a heat pipe. The heat transfer member 18 is disposed in contact with the end face 13a of the base portion 13 opposite the pipe portion 14. The provision of the heat transfer member 18 further uniforms the temperature between adjacent base portions 13 in the direction of cooling airflow.

[0041] 13 , the cooling device 1 may further include a heat transfer member 19 that extends in the direction of cooling airflow passing between the pipes 14a and transfers heat in the extension direction. The heat transfer member 19 is, for example, a heat pipe. The heat transfer member 19 is disposed through a groove formed in the second main surface 11b of the base plate 11, in contact with the end surface 13c of the base portion 13 facing the pipe portion 14. The provision of the heat transfer member 19 allows the base portions 13 adjacent to each other in the direction of cooling airflow to be more uniformly heated.

[0042] The cross-sectional shape of the heat transfer members 18, 19 perpendicular to the extension direction is not limited to a circle and may be a flattened shape. A flattened shape is a shape obtained by deforming a circle so that the width of a portion of the circle is narrower than the original circle, and includes an ellipse, a streamlined shape, an oval, etc. An oval shape refers to a shape obtained by connecting the outer edges of two circles having the same diameter with two straight lines.

[0043] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure.

[0044] REFERENCE SIGNS LIST 1, 2, 3 Cooling device, 11 Base plate, 11a First main surface, 11b Second main surface, 11c Recess, 11d Through hole, 12 Vapor chamber, 13 Base portion, 13a, 13c End surface, 13b First cavity, 14 Pipe portion, 14a Pipe, 14b Second cavity, 15 Refrigerant, 16 Sealing member, 17 Fins, 18, 19 Heat transfer member, 21 Electronic component, 22 Casing, 31 Housing, 31a Opening, 101 Electronic device.

Claims

1. A base plate having at least one recess formed on its first main surface, and at least one through hole formed extending from the bottom surface of the recess toward a second main surface opposite to the first main surface, The device comprises a base portion having a first cavity inside and housed in the recess, a pipe portion integrally formed with the base portion and having a second cavity inside that communicates with the first cavity, and having at least one pipe extending from the base portion and inserted through the through hole, and at least one vapor chamber having a refrigerant sealed in the first cavity and the second cavity, The vapor chamber dissipates heat transferred from the heating element attached to the first main surface in surface contact with the base portion to the surrounding air via the base portion and the pipe portion. The end face of the base portion that contacts the heating element and the first main surface of the base plate are located on the same plane. Cooling device.

2. The base portion is housed in the recess in a state where it is in surface contact with the bottom surface of the recess. The cooling device according to claim 1.

3. The pipe section has a plurality of the pipes, At least one through hole is formed in the bottom surface of the recess through which the multiple pipes are inserted. The base portion is housed in the recess in a state where it is in surface contact with the area around the through hole at the bottom surface of the recess. The cooling device according to claim 1 or 2.

4. The base portion has a flat plate shape, The bottom surface of the recess is flat. The cooling device according to claim 1 or 2.

5. The pipe extends in a direction perpendicular to the first main surface. The cooling device according to claim 1 or 2.

6. The pipe extends in a direction inclined from the direction perpendicular to the first main surface, and in a direction away from the base plate. The cooling device according to claim 1 or 2.

7. The pipe further comprises a plurality of fins attached to the aforementioned pipe. The cooling device according to claim 1 or 2.

8. The through hole in the base plate further includes a sealing member that contacts the base portion and the base plate. The cooling device according to claim 1 or 2.

9. The base plate has a plurality of recesses formed therein. The system comprises multiple vapor chambers, The multiple base portions are housed in a state where they abut each other in the multiple recesses, which are adjacent to each other in the direction of airflow for the cooling air passing between the pipes, and are in surface contact with multiple electronic components that are electrically connected in parallel to each other. The cooling device according to claim 1 or 2.

10. The multiple base portions are housed in a state in contact with each other in a plurality of recesses that are adjacent to each other in the direction of airflow for the cooling air passing between the pipes, and are in surface contact with a plurality of switching elements of the power conversion circuit that correspond to the same phase of the AC power input to the power conversion circuit or the AC power output from the power conversion circuit. The cooling device according to claim 9.

11. At least one of the base portions is provided adjacent to a plurality of electronic components that are electrically connected in parallel to each other, in the direction of airflow for the cooling air passing between the pipes. The cooling device according to claim 1 or 2.

12. At least one of the base portions is provided adjacent to the same base portion in the direction of airflow for the cooling air passing between the pipes, and is in surface contact with a plurality of switching elements included in a power conversion circuit, the plurality of switching elements corresponding to the same phase of the AC power input to the power conversion circuit or the AC power output from the power conversion circuit. The cooling device according to claim 11.

13. The system further includes a heat transfer member that extends in the direction of airflow for the cooling air passing between the pipes and transmits heat in the direction of extension. The cooling device according to claim 9.

14. The heat transfer member is positioned in contact with the end face of the base portion opposite to the pipe portion. The cooling device according to claim 13.

15. The heat transfer member is positioned in contact with the end face of the base portion facing the pipe portion. The cooling device according to claim 13.

16. Electronic components that generate heat when power is applied, An opening is formed, and the housing accommodates the electronic components, A cooling device according to claim 1 or 2, comprising: The electronic component is mounted on the first main surface of the base plate of the cooling device, in a state where it is in contact with the base portion of the vapor chamber of the cooling device. The cooling device is attached to the housing in a position where the base plate closes the opening. electronic equipment.