WO2017208461A1 - Boiling cooling device and electronic device having same mounted thereon - Google Patents

Abstract

A boiling cooling device (30) has: a plurality of heat receiving members (32a, 32b) that are disposed corresponding to a plurality of heat generating bodies (20a, 20b), respectively; a condensing section (31), which condenses and liquefies the vapor of a refrigerant (R) that has been heated and boiled by means of the heat receiving members; and a plurality of connecting pipes (36a, 36b) for transporting the refrigerant. The connecting pipes are: an upstream connecting pipe (36a) that connects to each other the condensing section and the heat receiving member closest to the condensing section; and another pipe, i.e., a downstream connecting pipe (36b) that connects to each other the heat receiving members that are disposed in the downstream of the upstream connecting pipe. The upstream connecting pipe (36a) and the downstream connecting pipe (36b) have single pipe structures, respectively.

Description

Boiling cooling device and electronic device equipped with the same

The present invention relates to a boiling cooling device using phase change cooling of a working fluid, and an electronic device equipped with the boiling cooling device.

In recent years, for example, electronic devices typified by servers, storage devices, network devices, and the like have semiconductor elements such as a plurality of CPUs (central processing units) mounted on circuit boards in order to improve processing speed and the like. . The electronic device has circuit boards mounted with high density in a box-shaped rack together with a hard disk device or the like.

Incidentally, a semiconductor element such as a CPU is a heating element that generates heat. In recent years, the calorific value tends to increase. And if a semiconductor device exceeds predetermined temperature, not only will it become impossible to maintain performance, but it may be damaged depending on the case. Therefore, the temperature management of the semiconductor element by cooling or the like is required, and a technique for efficiently cooling the semiconductor element that generates a large amount of heat is strongly demanded.

In such an electronic device, the semiconductor element is a heating element that generates heat. In recent years, in an electronic device, the density of semiconductor elements has been increased in order to improve the processing speed, and the amount of heat generated by the electronic device alone tends to increase, and the number of semiconductor elements mounted increases. Because of this tendency, the amount of heat generated by the entire apparatus tends to increase.

Conventionally, in an electronic device such as a server, generally, an air-cooling type cooling device has been widely used. However, the improvement of the cooling capacity of the air-cooled cooling device is already approaching its limit. Therefore, the provision of a new type of cooling system is expected, and as one of them, attention is focused on a cooling system using a refrigerant such as water.

The cooling device mounted on the electronic device is generally an air-cooling type. However, the air-cooling type cooling device is approaching the limit of the cooling capacity, and it is difficult to realize further improvement of the cooling capacity. For this reason, it has been studied to mount a new cooling system cooling device in place of the air cooling type cooling device in the electronic device. As a result, as a type of cooling device, a thermosiphon-type boiling cooling device using a refrigerant such as water as a working fluid and utilizing phase change cooling of the working fluid has been provided in recent years (see, for example, Patent Document 1). .

The boiling cooling device described in Patent Document 1 includes a plurality of boiling portions (heat receiving portions) equal to the number of heating elements, one condensing portion (heat radiating portion), a double pipe structure connecting pipe, It has the structure which has.

W02015 / 056288 publication

However, since the conventional boiling cooling device described in Patent Document 1 is a device having a complicated structure using a connecting tube having a double tube structure, it is difficult to reduce the size of the connecting tube and the entire device, There was a problem that the degree of freedom in designing the device was low and it was difficult to manufacture.

The present invention has been made to solve the above-described problems, and is a boiling cooling device that can be made relatively small in size and can improve the degree of design freedom, and an electronic device equipped with the same. The main purpose is to provide a device.

In order to achieve the above object, the present invention has a hollow portion for accommodating a refrigerant therein, is disposed corresponding to each of a plurality of heating elements, and is formed from each of the heating elements. A plurality of heat receiving members that receive heat to heat the refrigerant in the hollow portion, a condensing portion that condenses and liquefies the vapor of the refrigerant heated and boiled by each of the heat receiving members, and a plurality of connections that transport the refrigerant A plurality of connecting pipes, an upstream connecting pipe that connects the condensing part, which is an upstream part of the flow of the liquefied refrigerant, and the heat receiving member immediately adjacent thereto, and the other, It is a downstream connecting pipe that connects the heat receiving members arranged downstream of the upstream connecting pipe, and each of the upstream connecting pipe and the downstream connecting pipe has a single tube structure. A boiling cooling device characterized by And equipped with an electronic device.
Other means will be described later.

According to the present invention, the size can be made relatively small, and the degree of freedom in design can be improved.

It is a top view of the circuit board carrying the boiling cooling device concerning an embodiment. It is a sectional side view of a circuit board carrying a boiling cooling device concerning an embodiment. It is a top view of the boiling cooling device concerning an embodiment. It is a sectional side view of the boiling cooling device concerning an embodiment. It is a top view of a circuit board carrying a boiling cooling device concerning the 1st modification. It is a top view of a circuit board carrying a boiling cooling device concerning the 2nd modification. It is a sectional side view of a circuit board carrying a boiling cooling device concerning the 3rd modification. It is a sectional side view of the circuit board carrying the boiling cooling device which concerns on a 4th modification. It is a sectional side view of a circuit board carrying a boiling cooling device concerning the 5th modification. It is a sectional side view of the circuit board carrying the boiling cooling device which concerns on a 6th modification. It is a sectional side view of the circuit board carrying the boiling cooling device which concerns on a 7th modification. It is a partial section perspective view of a rack mount server system. It is a partial section perspective view of an electronic device carrying a boiling cooling device concerning an embodiment. It is a top view of the electronic device carrying the boiling cooling device concerning an embodiment. It is a top view (1) of the electronic device carrying the boiling cooling device which concerns on a modification. It is a top view (2) of the electronic device carrying the boiling cooling device which concerns on a modification.

Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. Each figure is only schematically shown so that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated example. Moreover, in each figure, the same code | symbol is attached | subjected about the common component and the same component, and those overlapping description is abbreviate | omitted.

[Embodiment]
<Configuration of circuit board and boiling cooling device mounted on the circuit board>
Hereinafter, the configuration of the circuit board (printed circuit board) 50 and the boiling cooling device 30 according to the present embodiment mounted on the circuit board 50 will be described with reference to FIGS. FIG. 1 is a diagram illustrating a configuration of the circuit board 50. FIG. 2 is a side sectional view of the circuit board 50 and shows the shape of the cut surface of the circuit board 50 cut along the line X1-X1 shown in FIG. FIG. 3 is a top view of the boiling cooling device 30. FIG. 4 is a side sectional view of the boiling cooling device 30.

Here, the case where the circuit board 50 is mounted on the server module 5 (see FIG. 12) will be described. The server module 5 (see FIG. 12) is an electronic device configured as a rack mount server accommodated in the rack cabinet 2 (see FIG. 12).

As shown in FIG. 1, a circuit board 50 includes two semiconductor elements 20a and 20b (see FIG. 2) such as a CPU as a heating element, and a printed wiring board (printed wiring) having the semiconductor elements 20a and 20b mounted on the surface. board) 10, a boiling cooling device 30 that cools the semiconductor elements 20a and 20b, and a cooling fan 40 that sends air (cooling air) to a condenser 31 that will be described later. Hereinafter, the semiconductor elements 20a and 20b are collectively referred to as “semiconductor element 20”.

Of the two semiconductor elements 20a and 20b (see FIG. 2), the semiconductor element 20a is an element closer to the condenser 31 described later, while the semiconductor element 20b is an element farther from the condenser 31 described later. It is. In the present embodiment, the height of the upper surface of each semiconductor element 20a, 20b is the same. That is, the thickness of each semiconductor element 20a, 20b is the same.

The boiling cooling device 30 is configured as a thermosiphon-type phase change module that uses a coolant such as water as a working fluid and uses phase change cooling of the working fluid.
“Phase change cooling” is a cooling technique that uses heat transfer when the working fluid changes from a liquid to a gas.
“Thermo siphon” is a method in which a working fluid is enclosed in a closed container having a boiling part and a condensing part, and the working fluid is heated and evaporated (vaporized) in the boiling part, and the working fluid is cooled in the condensing part. It is a mechanism for returning the working fluid condensed (liquefied) using gravity and condensed (liquefied) using gravity from the condensing part to the boiling part.

Hereinafter, the boiling cooling device may be referred to as a “phase change module”. Further, the working fluid may be referred to as “refrigerant”. Further, the liquefied refrigerant may be referred to as “liquid refrigerant” and the vaporized refrigerant vapor may be referred to as “refrigerant vapor”.

As shown in FIGS. 1 and 3, the phase change module (boiling cooling device) 30 transports refrigerant by two heat receiving members 32 a and 32 b that function as a boiling part, a condenser 31 that functions as a condensing part, and 2. The connecting pipes 36a and 36b are provided. Hereinafter, the heat receiving members 32a and 32b are collectively referred to as “heat receiving member 32”. The connecting pipes 36a and 36b are collectively referred to as “connecting pipe 36”.

Of the two heat receiving members 32 a and 32 b, the heat receiving member 32 a is a member closer to the condenser 31, while the heat receiving member 32 b is a member farther from the condenser 31. The heat receiving member 32a is attached to the surface of the semiconductor element 20a (see FIG. 2), which is a heating element, and receives heat from the semiconductor element 20a. On the other hand, the heat receiving member 32b is attached to the surface of the semiconductor element 20b (see FIG. 2), which is a heating element, and receives heat from the semiconductor element 20b.

Of the two connecting pipes 36a and 36b, the connecting pipe 36a is a pipe connecting the condenser 31 and the heat receiving member 32a in the immediate vicinity thereof, while the connecting pipe 36b is disposed downstream of the connecting pipe 36a. This is a pipe connecting the heat receiving member 32a and the heat receiving member 32b. Each of the connecting pipes 36a and 36b has a single pipe structure. In the present embodiment, the connecting pipes 36a and 36b are arranged so as to extend in the same direction when viewed from above (see FIGS. 1 and 3). The liquid refrigerant flows on the lower side inside the connecting pipes 36a and 36b, while the refrigerant vapor flows on the upper side inside the connecting pipes 36a and 36b.

In the present embodiment, “upstream” and “downstream” are based on the direction in which the liquid refrigerant flows (the liquid flow direction Aliq described later). Therefore, in this embodiment, the “condenser 31” is the most upstream part, and the “heat receiving member 32b” is the most downstream part. The connecting pipe 36a serves as an upstream connecting pipe, while the connecting pipe 36b serves as a downstream connecting pipe.

2 and 4, the heat receiving member 32a of the two heat receiving members 32a and 32b includes a lid 33a and a bottom plate 34a covered with the lid 33a. The bottom surface of the bottom plate 34a of the heat receiving member 32a is in contact with the surface of the semiconductor element 20a. On the other hand, the heat receiving member 32b includes a lid 33b and a bottom plate 34b covered with the lid 33b. The bottom surface of the bottom plate 34b of the heat receiving member 32b is in contact with the surface of the semiconductor element 20b. Hereinafter, the lids 33a and 33b are collectively referred to as “lid 33”. The bottom plates 34a and 34b are collectively referred to as “bottom plate 34”.

The lid 33 is made by, for example, processing a metal plate having excellent thermal conductivity, such as copper or aluminum alloy, into a shape narrowed down like a bowl. On the other hand, the bottom plate 34 is made by processing a metal plate having excellent thermal conductivity, such as copper or aluminum alloy, into a flat plate shape.

In the phase change module 30, the printed wiring board 10 is fixed with a fixing tool (not shown) such as a screw so that the bottom surfaces of the bottom plates 34a and 34b of the heat receiving members 32a and 32b are in contact with the surfaces of the corresponding semiconductor elements 20a and 20b. It is fixed to. In addition, in order to ensure favorable heat transfer between the bottom surfaces 34a and 34b of the heat receiving members 32a and 32b corresponding to the surfaces of the semiconductor elements 20a and 20b, heat conduction grease (not shown) is provided, respectively. It has been applied.

A hollow portion 32ia that accommodates the refrigerant R is formed in the heat receiving member 32a, and a boiling heat transfer portion 35a to which the heat of the semiconductor element 20a is transmitted is disposed in the hollow portion 32ia. . On the other hand, the heat receiving member 32b is formed with a hollow portion 32ib for accommodating the refrigerant, and the boiling heat transfer portion 35b to which the heat of the semiconductor element 20b is transmitted is disposed inside the hollow portion 32ib. Yes. Hereinafter, the hollow portions 32ia and 32ib are collectively referred to as “hollow portions 32i”. The boiling heat transfer parts 35a and 35b are collectively referred to as “boiling heat transfer part 35”.

The liquid refrigerant Rliq, which is the liquefied refrigerant R, is accumulated on the bottom side inside the hollow portion 32i, and the vaporized refrigerant is present in the space above the liquid level of the liquid refrigerant Rliq inside the hollow portion 32i. The refrigerant vapor Rst which is R is floating. The inside of the hollow part 32i is in a decompressed state. Therefore, the refrigerant R is easily boiled at a relatively low temperature.

The liquid refrigerant Rliq flows from the condenser 31 toward the heat receiving member 32b (see arrow Aliq). Arrow Aliq indicates the direction of liquid flow. On the other hand, the refrigerant vapor Rst flows from the heat receiving member 32b toward the condenser 31 (see arrow As). Arrow Ast indicates the direction of steam flow.

The boiling heat transfer section 35 is disposed near the center inside the heat receiving member 32 in a top view. The boiling heat transfer section 35 has a porous structure in order to promote evaporation (vaporization) of the refrigerant R. That is, the boiling heat transfer part 35 has a structure provided with minute uneven projections and holes. The boiling heat transfer section 35 is made, for example, by machining a vaporization promoting plate having a porous structure. The vaporization promotion plate is made by processing a metal plate having excellent thermal conductivity, such as copper or aluminum alloy. The boiling heat transfer section 35 is joined to the bottom plate 34 by pressure welding, brazing, or the like. However, the boiling heat transfer section 35 can be formed integrally with the bottom plate 34 by making the surface of the bottom plate 34 porous and machining the surface of the bottom plate 34.

The heat receiving member 32 heats and evaporates (vaporizes) the refrigerant R accommodated in the hollow portion 32i by transferring the heat of the semiconductor element 20 to the boiling heat transfer portion 35 through the bottom plate 34. As a result, the liquid refrigerant Rliq is changed to the refrigerant vapor Rst inside the hollow portion 32i.

The condenser 31 includes a hollow portion 31i that accommodates the refrigerant R inside the upper side, and a plurality of fins 31f on the lower side. The condenser 31 has a structure in which the hollow portion 31i in which the refrigerant R is accommodated is disposed on the upper side and the fins 31f are disposed on the lower side. Thereby, the condenser 31 can make thickness thin.

The bottom surface of the hollow portion 31i of the condenser 31 is disposed at a position higher than the bottom surfaces (the top surfaces of the bottom plates 34a and 34b) of the hollow portions 32ia and 32ib of the heat receiving members 32a and 32b. The cooling fan 40 (see FIG. 1) sends air (cooling air) in the direction of the fins 31f (see arrow Aair). Arrow Aair shows the direction of the cooling air flow. The air (cooling air) sent by the cooling fan 40 (see FIG. 1) passes around the fins 31f. At that time, the condenser 31 releases the heat of the refrigerant vapor Rst inside the hollow portion 31i to the air (cooling air) through the fins 31f. Thereby, the condenser 31 cools and liquefies the refrigerant | coolant vapor | steam Rst inside the hollow part 31i. As a result, the refrigerant vapor Rst returns to the liquid refrigerant Rliq inside the hollow portion 31i.

Such a phase change module 30 can circulate the working fluid between the most upstream condenser 31 and the downstream heat receiving members 32a and 32b without using external power such as an electric pump.

By the way, the conventional boiling cooling apparatus described in Patent Document 1 has a plurality of boiling parts (heat receiving parts) having the same number as the number of heating elements, one condensing part (heat radiating part), and a double tube structure. And a connecting pipe. Such a conventional boiling cooling device has a structure that makes it difficult to return the liquid to the boiling portion far from the condensing portion. For this reason, in the conventional boiling cooling device, dryout due to liquid withering occurs in the boiling part far from the condensing part, and as a result, the temperature of the heating element far from the condensing part can rapidly increase. There was sex. Thereby, the conventional boiling cooling apparatus may impair the reliability of the electronic device mounted.

In consideration of such a phenomenon, the phase change module 30 causes dryout due to liquid drainage in the heat receiving member 32b on the downstream side (the side far from the condenser 31), and as a result, the semiconductor element 20b on the downstream side A structure that can prevent the temperature from rising is preferable. That is, the phase change module 30 preferably has a structure that can satisfactorily return the liquid refrigerant Rliq to the heat receiving member 32b that is the most downstream portion. Therefore, the phase change module 30 has the following structure.

For example, in the phase change module 30, the upper surface of the bottom plate 34a of the heat receiving member 32a on the upstream side (side closer to the condenser 31) is higher than the upper surface of the bottom plate 34b of the heat receiving member 32b on the downstream side (side far from the condenser 31). It is placed at a high position. In other words, the upper surface of the bottom plate 34b of the downstream heat receiving member 32b is disposed at a position lower than the upper surface of the bottom plate 34a of the upstream heat receiving member 32a. The thicknesses of the bottom plates 34a and 34b of the heat receiving members 32a and 32b are adjusted so that the upper surfaces satisfy such a height position relationship.

Moreover, the height of the boiling heat transfer portions 35a and 35b is lower as the boiling heat transfer portion 35b of the downstream heat receiving member 32b is farther from the condensing portion 31. Further, the height of the ceiling of the hollow portions 32ia and 32ib of the heat receiving member 32a32b is lower as the hollow portion 32ib of the heat receiving member 32b on the downstream side farther from the condensing portion 31 is lower.

In the phase change module 30, the upper surface of the condenser 31 and the upper surfaces of the heat receiving members 32a and 32b are arranged so that the upper surface of the condenser 31 is the highest, and the upper surface of the heat receiving member 32a and the upper surface of the heat receiving member 32b are lowered in this order. The height position is set. Further, the height positions of the inner bottom portions of the connecting tubes 36a and 36b are set so that the inner bottom portion of the downstream connecting tube 36b is lower than the inner bottom portion of the upstream connecting tube 36a.

Such a phase change module 30 allows the liquid refrigerant Rliq to flow well from the heat receiving member 32a on the upstream side (side near the condenser 31) toward the heat receiving member 32b on the downstream side (side far from the condenser 31). it can. Thereby, the phase change module 30 can perform liquid return favorably toward the heat receiving member 32b which is the most downstream part from the condenser 31 which is the most upstream part. As a result, the phase change module 30 reduces the amount of the liquid refrigerant Rliq retained in the upstream heat receiving member 32a as much as possible and cools the downstream semiconductor element 20b (see FIG. 2) sufficiently. The liquid refrigerant Rliq can be flowed to the heat receiving member 32b on the downstream side. Therefore, the phase change module 30 can prevent the dry-out due to the liquid withering in the downstream heat receiving member 32b, and prevents a rapid increase in temperature in each heating element (particularly, the downstream semiconductor element 20b). can do.

The relationship between the height positions of the upper surfaces of the bottom plates 34a and 34b may be considered as a relationship based on the upper surface of the printed wiring board 10 (see FIG. 2). That is, on the basis of the upper surface of the printed wiring board 10 (see FIG. 2), the distance from the upper surface of the printed wiring board 10 to the upper surface of the bottom plate 34a of the upstream heat receiving member 32a is downstream from the upper surface of the printed wiring board 10. The heat receiving member 32b is larger than the distance to the upper surface of the bottom plate 34b.

Also, as described above, the upper surface of the bottom plate 34a of the upstream heat receiving member 32a is disposed at a position higher than the upper surface of the bottom plate 34b of the downstream heat receiving member 32b. Therefore, the phase change module 30 has a structure in which the inner bottom portion of the upstream connecting pipe 36a is disposed at a position higher than the inner bottom portion of the downstream connecting pipe 36b. When trying to realize such a structure, if the diameter of the upstream connecting pipe 36a is set to be smaller than the diameter of the downstream connecting pipe 36b, the upstream connecting pipe 36a and the downstream connecting pipe 36a The flow path resistance changes with the connecting pipe 36b. Thereby, the flow of the liquid refrigerant Rliq may be hindered. Therefore, in the present embodiment, in order to realize a good flow of the liquid refrigerant Rliq, each connection is made so that the cross-sectional area of the upstream connection pipe 36a and the cross-sectional area of the downstream connection pipe 36b are substantially the same. The flatness of the tubes 36a and 36b is adjusted. Specifically, the flattening rate of each of the connecting pipes 36a and 36b increases as the connecting pipe on the upstream side near the condensing unit 31 increases. That is, the cross-sectional shape of the upstream connecting pipe 36a is wider than the cross-sectional shape of the downstream connecting pipe 36b, and the vertical width is narrow. In other words, the cross-sectional shape of the downstream connecting pipe 36b is narrower than the cross-sectional shape of the upstream connecting pipe 36a and has a wide vertical width.

In the present embodiment, the phase change module 30 is mounted on the circuit board 50 mounted on the server module 5 (see FIG. 12) which is a rack mount server. The rack mount server is defined such that the height of the housing is within 1U (or 2U). “U” is the minimum dimension of the rack mounting height and is 1U = 44.45 mm (1.75 inches). Therefore, the thickness from the upper end portion to the lower end portion of the phase change module 30 is set to a value that allows the circuit board 50 to be mounted on the server module 5 (see FIG. 12) with the phase change module 30 mounted. ing.

Here, “the upper end portion of the phase change module 30” is the upper surface of the condenser 31. The “lower end portion of the phase change module 30” refers to any one or more of the lower end of the fin 31f of the condenser 31, the bottom surface of the bottom plate 34a of the heat receiving member 32a, and the bottom surface of the bottom plate 34b of the heat receiving member 32b. It has become.

By the way, the condensing part (heat radiating part) of the conventional boiling cooling apparatus described in Patent Document 1 needs to receive refrigerant vapor generated in each of the plurality of boiling parts (heat receiving parts) separately. Therefore, the condensing part (heat radiation part) of the conventional boiling cooling device has a structure that partitions the internal space. Such a conventional boiling cooling device has a structure in which it is difficult to reduce the size of the condensing part (heat dissipating part) because a useless space that is not used for accommodating the refrigerant vapor exists inside the condensing part (heat dissipating part). Yes.

On the other hand, the condensing part (condenser 31) of the phase change module 30 according to the present embodiment needs to separately receive the refrigerant vapor Rst generated in each of the plurality of boiling parts ( heat receiving members 32a and 32b). Absent. Therefore, the condensing part (condenser 31) of the phase change module 30 can configure the internal space as a single hollow part 31i having a relatively large capacity. Since such a phase change module 30 does not have a useless space that is not used for accommodating the refrigerant vapor Rst inside the condenser (condenser 31), the size of the condenser (condenser 31) can be easily reduced. be able to. Thereby, the phase change module 30 has a thickness from the upper end to the lower end so that the circuit board 50 can be mounted on the server module 5 (see FIG. 12) in a state where the phase change module 30 is mounted. Can be set. Therefore, the circuit board 50 on which the phase change module 30 is mounted can be mounted on the server module 5 (see FIG. 12) that is a rack mount server.

In such a configuration, the heat generated in the semiconductor element 20 is transmitted from the surface of the semiconductor element 20 to the bottom plate 34 of the heat receiving member 32 via heat conduction grease (not shown), and is disposed from the bottom plate 34 to the inside of the hollow portion 32i. Is transmitted to the boiling heat transfer section 35.

Thereby, in the hollow portion 32i of the heat receiving member 32, the liquid refrigerant Rliq boils under reduced pressure and evaporates. As a result, refrigerant vapor Rst is generated. The refrigerant vapor Rst flows from the heat receiving member 32 toward the condenser 31 through the inside of the connecting pipe 36.

The refrigerant vapor Rst that has reached the condenser 31 is liquefied by being cooled by the condenser 31 and returns to the liquid refrigerant Rliq. The liquid refrigerant Rliq flows from the condenser 31 toward the heat receiving member 32 through the inside of the connecting pipe 36 due to gravity. At this time, the liquid refrigerant Rliq first reaches the hollow portion 32ia of the upstream heat receiving member 32a. Then, the liquid refrigerant Rliq that has overflowed from the hollow portion 32ia of the upstream heat receiving member 32a does not stop at the upstream heat receiving member 32a, and travels from the upstream heat receiving member 32a to the downstream heat receiving member 32b. The flow reaches the hollow portion 32ib of the heat receiving member 32b on the downstream side.

As described above, the boiling heat transfer section 35 has a porous structure.
In such a boiling heat transfer section 35, when the amount of input heat is small, only a small amount of the liquid refrigerant Rliq evaporates (vaporizes), and the film thickness of the liquid refrigerant Rliq increases. As a result, the liquid refrigerant Rliq is impregnated into the holes of the boiling heat transfer section 35 to fill the holes. Therefore, the boiling heat transfer section 35 can exhibit stable evaporation performance (vaporization performance) unless the liquid refrigerant Rliq is depleted.
On the other hand, when the amount of input heat is large, the liquid refrigerant Rliq filling each hole is evaporated (vaporized), and the film thickness of the liquid refrigerant Rliq is reduced. As a result, the thin portion of the liquid refrigerant Rliq increases, and the evaporation (vaporization) of the liquid refrigerant Rliq is promoted. Therefore, the boiling heat transfer part 35 can improve the heat dissipation performance and increase the amount of heat transport.

Such a boiling heat transfer section 35 can promote the evaporation (vaporization) of the liquid refrigerant Rliq depending on the temperature rise when the amount of input heat increases. Further, the boiling heat transfer section 35 can further promote the evaporation (vaporization) of the liquid refrigerant Rliq depending on the increase in the amount of the refrigerant vapor Rst. Therefore, the boiling heat transfer unit 35 can greatly increase the heat transport amount and improve the cooling performance as the input heat amount is larger.

<Main features>
(1) The phase change module 30 according to the present embodiment has a structure in which the refrigerant R is transported using connecting pipes 36a and 36b having a single pipe structure. Unlike the conventional boiling cooling device described in Patent Document 1, such a phase change module 30 has a simple structure, so that it can be made relatively small in size and has a high degree of design freedom. Can be improved. Therefore, it can be manufactured relatively easily.

(2) The phase change module 30 is configured so that the upper surface of the bottom plate 34a of the heat receiving member 32a on the upstream side (side closer to the condenser 31) is higher than the upper surface of the bottom plate 34b of the heat receiving member 32b on the downstream side (side far from the condenser 31). It is placed at a high position. The connecting pipes 36a and 36b are formed such that the inner bottom portion of the downstream connecting pipe 36b is lower than the inner bottom portion of the upstream connecting pipe 36a. Such a phase change module 30 can satisfactorily return the liquid from the condenser 31 that is the most upstream part toward the heat receiving member 32b that is the most downstream part. As a result, the phase change module 30 can prevent dry-out due to liquid withering in the downstream heat receiving member 32b, and can prevent temperature rise of each heating element (particularly, the downstream semiconductor element 20b). it can.

(3) The phase change module 30 has a structure in which the flatness of each connecting pipe 36 is adjusted so that the cross-sectional area of the upstream connecting pipe 36a and the cross-sectional area of the downstream connecting pipe 36b are substantially the same. It has become. That is, the cross-sectional shape of the upstream connecting pipe 36a is wider than the cross-sectional shape of the downstream connecting pipe 36b, and the vertical width is narrow. Such a phase change module 30 can prevent the flow resistance from changing between the upstream connecting pipe 36a and the downstream connecting pipe 36b, and as a result, a good flow of the liquid refrigerant Rliq is realized. be able to.

(4) The phase change module 30 can easily reduce the size of the condensing unit (condenser 31) because there is no useless space in the condensing unit (condenser 31) that is not used to accommodate the refrigerant vapor Rst. be able to. Thereby, the phase change module 30 has a thickness from the upper end to the lower end so that the circuit board 50 can be mounted on the server module 5 (see FIG. 12) in a state where the phase change module 30 is mounted. Can be set. Therefore, the circuit board 50 on which the phase change module 30 is mounted can be mounted on the server module 5 (see FIG. 12) that is a rack mount server.

(5) Since the phase change module 30 has a relatively simple structure, it can be manufactured at low cost. Moreover, the phase change module 30 can circulate the working fluid between the most upstream condenser 31 and the downstream heat receiving members 32a and 32b without using external power such as an electric pump. Therefore, the phase change module 30 is excellent in energy saving, and can efficiently and reliably cool the heating elements ( semiconductor elements 20a and 20b).

By using such a phase change module 30, the circuit board 50 can satisfactorily return the liquid to the downstream boiling portion (here, the heat receiving member 32 b), and therefore the downstream boiling portion (here Then, it is possible to suppress the liquid withering at the heat receiving member 32b). As a result, the circuit board 50 can sufficiently cool each semiconductor element 20 regardless of the mounting position of each semiconductor element 20. Such a circuit board 50 can prevent a rapid increase in temperature at each heating element (particularly, the semiconductor element 20b on the downstream side), and can provide a highly reliable electronic device.

It should be noted that the phase change module 30 according to the present embodiment can be modified as, for example, the phase change modules 30A to 30G shown in FIGS. Hereinafter, the configuration of the phase change modules 30A to 30G according to each modification will be described with reference to FIGS.

<First Modification>
FIG. 5 is a top view of a circuit board 50A on which the phase change module 30A according to the first modification is mounted. As shown in FIG. 5, the phase change module 30 </ b> A according to the first modification has connecting pipes 36 a and 36 b extending in different directions in a top view as compared with the phase change module 30 according to the embodiment (see FIG. 1). It is different in that the structure is so arranged.

That is, the phase change module 30 (see FIG. 1) according to the embodiment has a structure in which the condenser 31, the connecting pipe 36a, the heat receiving member 32a, the connecting pipe 36b, and the heat receiving member 32b are arranged on a straight line. On the other hand, the phase change module 30A according to the first modification has a structure in which the condenser 31, the connecting pipe 36a, the heat receiving member 32a, the connecting pipe 36b, and the heat receiving member 32b are not arranged on a straight line. .

The circuit board 50A has a structure in which two semiconductor elements 20a and 20b are arranged under the two heat receiving members 32a and 32b of the phase change module 30A.

The height positions of the upper surfaces of the condenser 31 and the heat receiving members 32a and 32b are set so that the upper surface of the condenser 31 is the highest, and the upper surface of the heat receiving member 32a and the upper surface of the heat receiving member 32b are lowered in this order. The height position of the inner bottom portions of the connecting pipes 36a and 36b is set so that the inner bottom portion of the downstream connecting pipe 36b is lower than the inner bottom portion of the upstream connecting pipe 36a. The phase change module 30A according to the first modification is the same as the phase change module 30 according to the embodiment.

Such a phase change module 30A can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the downstream heat receiving member 32b, similarly to the phase change module 30 according to the embodiment.

<Second Modification>
FIG. 6 is a top view of a circuit board 50B on which the phase change module 30B according to the second modification is mounted. As shown in FIG. 6, the phase change module 30B according to the second modified example is a combination of the most upstream side connection pipe and the downstream side connection pipe, as compared with the phase change module 30 according to the embodiment (see FIG. 1). It is different in that it has a structure having a plurality of transport paths for the refrigerant R.

That is, the phase change module 30 (see FIG. 1) according to the embodiment has a structure including only a single transportation path in which the most upstream side connecting pipe 36a and the downstream side connecting pipe 36b are combined. In contrast, the phase change module 30B according to the second modification includes a first transport path in which the most upstream side connection pipe 36a and the downstream side connection pipe 36b are combined, and the most upstream side connection pipe 36a2 and the downstream side connection. It has a structure provided with two systems of transport paths, that is, a second transport path combined with the pipe 36b2.

The connecting pipes 36a and 36b of the first transport path are arranged so as to extend in the same direction when viewed from above. Further, the connecting pipes 36a2 and 36b2 of the second transport path are arranged so as to extend in the same direction when viewed from above.

The circuit board 50B has a structure in which two semiconductor elements 20a and 20b are arranged under the two heat receiving members 32a and 32b of the phase change module 30B.

The height positions of the upper surfaces of the condenser 31 and the heat receiving members 32a and 32b are set so that the upper surface of the condenser 31 is the highest, and the upper surface of the heat receiving member 32a and the upper surface of the heat receiving member 32b are lowered in this order. The height position of the inner bottom portions of the connecting pipes 36a and 36b is set so that the inner bottom portion of the downstream connecting pipe 36b is lower than the inner bottom portion of the upstream connecting pipe 36a. The phase change module 30B according to the second modification is the same as the phase change module 30 according to the embodiment.

Such a phase change module 30B can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the downstream heat receiving member 32b, similarly to the phase change module 30 according to the embodiment.

<Third Modification>
FIG. 7 is a side sectional view of a circuit board 50C on which the phase change module 30C according to the third modification is mounted. As illustrated in FIG. 7, the phase change module 30C according to the third modified example has a connecting pipe 36c and a heat receiving member 32c on the downstream side of the heat receiving member 32b as compared with the phase change module 30 according to the embodiment (see FIG. 2). It is different in that it has.

The heat receiving member 32c includes a bottom plate 34c. Further, the heat receiving member 32c includes a boiling heat transfer portion 35c therein.

The circuit board 50C has a structure in which three semiconductor elements 20a, 20b, and 20c are disposed under the three heat receiving members 32a, 32b, and 32c of the phase change module 30C. That is, the circuit board 50C has a structure in which the number of mounted semiconductor elements 20 is larger than that of the circuit board 50 according to the embodiment.

The height positions of the upper surfaces of the bottom plates 34a, 34b, and 34c of the heat receiving members 32a, 32b, and 32c become lower in the order of the heat receiving member 32a on the most upstream side, the heat receiving member 32b on the middle flow side, and the heat receiving member 32c on the most downstream side. Is set to Further, the height positions of the inner bottom portions of the connecting pipes 36a, 36b, and 36c are set so as to become lower in the order of the connecting pipe 36a on the most upstream side, the connecting pipe 36b on the intermediate stream side, and the connecting pipe 36c on the most downstream side. .

Note that the upper surfaces of the semiconductor elements 20a, 20b, and 20c of the circuit board 50C have the same height. Therefore, the bottom plates 34a, 34b, 34c of the heat receiving members 32a, 32b, 32c are: (a) the height position of the upper surface of the bottom plates 34a, 34b, 34c is the heat receiving member 32a on the most upstream side, the heat receiving member 32b on the intermediate flow side, The condition that the heat receiving member 32c on the downstream side is set to become lower in order and the condition that (b) the bottom plates 34a, 34b, and 34c are set to have the same height are satisfied. As such, its thickness is set.

Note that the flatness of each of the connecting pipes 36a, 36b, 36c is adjusted so that the cross-sectional areas of the connecting pipes 36a, 36b, 36c are substantially the same in order to achieve a good flow of the liquid refrigerant Rliq. ing. That is, the cross-sectional shape of each connecting pipe 36a, 36b, 36c is such that the upstream connecting pipe is wider in width and narrower in vertical length. In other words, the cross-sectional shape of each connecting pipe 36a, 36b, 36c is such that the downstream connecting pipe has a narrower lateral width and a wider vertical width.

Such a phase change module 30C can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the heat receiving members 32b and 32c on the downstream side.

<Fourth Modification>
FIG. 8 is a side sectional view of a circuit board 50D on which the phase change module 30D according to the fourth modification is mounted. As shown in FIG. 8, the circuit board 50D according to the fourth modified example is different from the circuit board 50C according to the third modified example (see FIG. 7) in place of the semiconductor elements 20a, 20b, and 20c. , 25b, and 25c are different. Each of the semiconductor elements 25a, 25b, and 25c is a semiconductor element in which either one or both of the height (thickness) of the upper surface and the shape of the upper surface are different. Hereinafter, the semiconductor elements 25a, 25b, and 25c are collectively referred to as “semiconductor element 25”. Further, the phase change module 30D according to the fourth modified example has either the height of the bottom surface of the bottom plate 34 or the shape of the top view of each heat receiving member 32 as compared with the phase change module 30C according to the third modified example (see FIG. 7). One or both are different in that they are set in accordance with the corresponding semiconductor element 25.

For example, FIG. 8 shows a state in which the upper surface (thickness) of each semiconductor element 25a, 25b, 25c is different. In this state, the heights of the bottom surfaces of the bottom plates 34a, 34b, 34c of the heat receiving members 32a, 32b, 32c of the phase change module 30D (that is, the thicknesses of the bottom plates 34a, 34b, 34c) correspond to the corresponding semiconductor elements 25a. , 25b, 25c are set according to the height of the upper surface.

The height positions of the upper surfaces of the bottom plates 34a, 34b, and 34c of the heat receiving members 32a, 32b, and 32c become lower in the order of the heat receiving member 32a on the most upstream side, the heat receiving member 32b on the middle flow side, and the heat receiving member 32c on the most downstream side. The heights of the inner bottom portions of the connecting pipes 36a, 36b, and 36c are set in the order of the upstream-most connecting pipe 36a, the middle-stream connecting pipe 36b, and the downstream-most connecting pipe 36c. The phase change module 30 </ b> D according to the fourth modification is the same as the phase change module 30 </ b> C according to the third modification.

Similar to the phase change module 30C according to the third modification, the phase change module 30D can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the downstream heat receiving members 32b and 32c. . Moreover, the phase change module 30D can be suitably mounted on the circuit board 50D on which the semiconductor elements 25a, 25b, and 25c having different one or both of the top surface height (thickness) and the top view shape are mounted. .

<Fifth Modification>
FIG. 9 is a side sectional view of a circuit board 50E on which the phase change module 30E according to the fifth modification is mounted. As shown in FIG. 9, the phase change module 30E according to the fifth modification has a downstream height lower than the upstream height compared to the phase change module 30 according to the embodiment (see FIG. 2). Thus, the connection pipe 36b is different in that it is disposed at an inclination.

It should be noted that the upper surface of the bottom plate 34a of the upstream heat receiving member 32a is located higher than the upper surface of the bottom plate 34b of the downstream heat receiving member 32b, and the inner bottom portion of the downstream connecting pipe 36b is the upstream side. The phase change module 30E according to the fifth modification is the same as the phase change module 30 according to the embodiment in that the connection pipe 36a is formed so as to be lower than the inner bottom portion.

Such a phase change module 30E can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the heat receiving member 32b on the downstream side, similarly to the phase change module 30 according to the embodiment. In addition, since the phase change module 30E has the connecting pipe 36b inclined downward toward the downstream side, the liquid refrigerant Rliq is supplied to the downstream heat receiving member 32b more efficiently than the phase change module 30 according to the embodiment. It can flow.

<Sixth Modification>
FIG. 10 is a side sectional view of a circuit board 50F on which the phase change module 30F according to the sixth modification is mounted. As shown in FIG. 10, the phase change module 30F according to the sixth modification has a downstream height higher than the upstream height compared to the phase change module 30D according to the fourth modification (see FIG. 8). The connection pipes 36b and 36c are different in that they are arranged so as to be lowered.

Similar to the phase change module 30D according to the fourth modified example, such a phase change module 30F can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the heat receiving members 32b and 32c on the downstream side. . Moreover, since the connection pipes 36b and 36c are inclined downward toward the downstream side, the phase change module 30F is more efficient than the phase change module 30D according to the fourth modification, and the downstream heat receiving members 32b and 32c. In addition, the liquid refrigerant Rliq can flow.

<Seventh Modification>
FIG. 11 is a side sectional view of a circuit board 50G on which the phase change module 30G according to the seventh modification is mounted. As shown in FIG. 11, the circuit board 50G according to the seventh modification example is different from the circuit board 50F according to the sixth modification example (see FIG. 10) in place of the semiconductor element 20 (20a, 20b, 20c). The semiconductor device 25 (25a, 25b, 25c) is different in that either one or both of the height (thickness) of the upper surface and the shape of the upper surface is different. Further, the phase change module 30G according to the seventh modified example has either the height of the bottom surface of the bottom plate 34 of each heat receiving member 32 or the shape of the top view as compared with the phase change module 30F according to the sixth modified example (see FIG. 10). One or both are different in that they are set in accordance with the corresponding semiconductor element 25.

For example, FIG. 11 shows a state in which the upper surface (thickness) of each semiconductor element 25a, 25b, 25c is different. In this state, the height of the bottom surfaces of the bottom plates 34a, 34b, 34c of the heat receiving members 32a, 32b, 32c of the phase change module 30G (that is, the thickness of the bottom plates 34a, 34b, 34c) corresponds to the corresponding semiconductor element 25a. , 25b, 25c are set according to the height of the upper surface.

The height positions of the upper surfaces of the bottom plates 34a, 34b, and 34c of the heat receiving members 32a, 32b, and 32c become lower in the order of the heat receiving member 32a on the most upstream side, the heat receiving member 32b on the middle flow side, and the heat receiving member 32c on the most downstream side. The heights of the inner bottom portions of the connecting pipes 36a, 36b, and 36c are set in the order of the upstream-most connecting pipe 36a, the middle-stream connecting pipe 36b, and the downstream-most connecting pipe 36c. The phase change module 30G according to the seventh modified example is the same as the phase change module 30F according to the sixth modified example in that it is set to be.

Similar to the phase change module 30F according to the sixth modification, such a phase change module 30G can flow the liquid refrigerant Rliq satisfactorily so that dryout does not occur in the downstream heat receiving members 32b and 32c. . Moreover, the phase change module 30G can be mounted on the circuit board 50G on which the semiconductor elements 25a, 25b, and 25c having different upper surface heights are mounted.

<Electronic device with boiling cooling device>
Hereinafter, the configuration of the server module 5 will be described with reference to FIGS. The server module 5 is an electronic device on which the phase change module 30 (including the phase change modules 30A to 30G according to each modification) is mounted.

FIG. 12 is a partial cross-sectional perspective view of the rack mount server system 1. FIG. 13 is a partial cross-sectional perspective view of the server module 5 on which the phase change module 30 is mounted. FIG. 14 is a top view of the server module 5. FIG. 15 is a top view of the server module 5 on which the phase change module 30A according to the first modification is mounted. FIG. 16 is a top view of the server module 5 on which the phase change module 30C according to the third modification is mounted.

As shown in FIG. 12, the server module 5 is accommodated in the rack cabinet 2 of the rack mount server system 1. A rack mount server system 1 includes a rack cabinet 2, a front door 3, and a back door 4, and a system in which a plurality of server modules 5 formed in a predetermined shape and size are detachably accommodated therein. It is.

As shown in FIGS. 13 and 14, the server module 5 includes a hard disk drive device 6, cooling fans 7 and 7 a, a power supply communication block 8, and a circuit board 50 on which the phase change module 30 is mounted. ing. However, in the example shown in FIGS. 13 and 14, the cooling fan 40 (see FIGS. 1 and 2) is excluded from the circuit board 50. 13 and 14 show the configuration of the server module 5 with the lid (not shown) removed.

The hard disk drive device 6 is a large capacity recording device. In consideration of maintainability, the hard disk drive device 6 has one of the front and rear surfaces of the server module 5 (for example, the right side in the example shown in FIG. 13 and the left side in the example shown in FIG. 14). A plurality (three in the example shown in FIGS. 13 and 14) are arranged in a concentrated manner.

The cooling fan 7 is a device that sends air (cooling air) to the hard disk drive device 6 and the circuit board 50 that are heating elements. In the example shown in FIGS. 13 and 14, four cooling fans 7 are arranged behind the hard disk drive device 6.

The cooling fan 7a is a device that sends air (cooling air) to the power communication block 8 that is a heating element. In the example shown in FIGS. 13 and 14, one cooling fan 7 is disposed behind the power supply communication block 8.

The power supply communication block 8 is a mechanism that houses a power supply unit (not shown) and a communication interface (not shown) such as a LAN. A power supply unit (not shown) of the power communication block 8 supplies power to the hard disk drive device 6, the cooling fans 7 and 7a, the semiconductor elements 20a and 20b of the circuit board 50, and the like.

The circuit board 50 is connected to the hard disk drive 6 and the cooling fans 7 and 7a so that the air (cooling air) sent from the cooling fan 7 hits the fins 31f (see FIG. 2) of the condenser 31 of the phase change module 30. It is arranged at a position avoiding the block 8.

Since the server module 5 includes the circuit board 50 on which the phase change module 30 is mounted, the temperature of each heating element (particularly, the downstream semiconductor element 20b) mounted on the circuit board 50 is measured. A sudden rise can be prevented. In addition, since the server module 5 does not use external power such as an electric pump, it is possible to cool each heating element ( semiconductor elements 20a and 20b) efficiently and reliably with less power.

In addition, since the circuit board 50 receives air (cooling air) from the cooling fan 7, a dedicated cooling fan 40 (see FIGS. 1 and 2) for cooling the semiconductor element 20 such as a CPU as a heating element is excluded. It has a structured. Since such a circuit board 50 has a simple structure without the cooling fan 40, it can be made relatively small in size. Thereby, since the circuit board 50 can improve the freedom degree of design, it can be mounted in the electronic device with a comparatively high calorific value for which high-density mounting of components is required. Moreover, such a circuit board 50 can reduce manufacturing cost.

The condenser 31 is preferably arranged so as to cover the exhaust surfaces of the plurality of cooling fans 7. As a result, the condenser 31 can receive air (cooling air) from the cooling fan 7 that has not failed even if any of the cooling fans 7 has failed and stopped. Therefore, in this case, the phase change module 30 can continue cooling the refrigerant vapor Rst in the condenser 31. Therefore, the phase change module 30 can ensure continuity of cooling with respect to the refrigerant vapor Rst, and as a result, can be suitably used as a cooling device for a heating element of an electronic device.

Further, the condenser 31 is more preferably arranged close to the cooling fan 7 having a small area facing the condenser 31. As a result, the condenser 31 can reliably receive air (cooling air) from the cooling fan 7 that has not failed even if one of the cooling fans 7 has failed and stopped. Therefore, in this case, the phase change module 30 can improve the continuity of cooling with respect to the refrigerant vapor Rst.

As shown in FIG. 15, the server module 5 can be mounted with a circuit board 50 </ b> A on which the phase change module 30 </ b> A is mounted instead of the circuit board 50. As shown in FIG. 16, the server module 5 can be mounted with a circuit board 50 </ b> C on which the phase change module 30 </ b> C is mounted instead of the circuit board 50. Further, the server module 5 replaces the circuit board 50 with circuit boards 50B, 50D to 50G on which the phase change modules 30B, 30D to 30G according to other modifications other than the circuit board 50A and the circuit board 50C are mounted. Can be installed.

As described above, according to the phase change module 30 (including the phase change modules 30A to 30G according to the respective modifications) that is the boiling cooling device according to the present embodiment, the size can be made relatively small and the design can be made. The degree of freedom can be improved.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. In addition, a part of the configuration of the embodiment can be replaced with another configuration, and another configuration can be added to the configuration of the embodiment. Moreover, it is possible to add / delete / replace other configurations for a part of each configuration.

For example, the phase change module 30 (including the phase change modules 30A to 30G according to each modification) according to the above-described embodiment can be mounted not only on the server module 5 but also in various forms of electronic devices.

Further, for example, the circuit board 50 can increase the number of semiconductor elements 20 mounted. Accordingly, the phase change module 30 (including the phase change modules 30A to 30G according to the respective modifications) can increase the number of heat receiving members 32 mounted. In this case, the height position of the upper surface of the bottom plate 34 of each heat receiving member 32 and the height position of the inner bottom portion of each connection pipe 36 are set to higher positions on the upstream side (that is, lower positions on the downstream side). . The cross-sectional shape of each connecting pipe 36 is such that the upstream connecting pipe has a wider width and a smaller vertical width (that is, the downstream connecting pipe has a smaller width and a wider vertical width). )become. Thereby, even if the circuit board 50 is a case where the mounting number of the semiconductor elements 20 is increased, the plurality of semiconductor elements 20 can be efficiently cooled.

Further, for example, the circuit board 50 can change the arrangement position of the semiconductor element 20. In accordance with this, the phase change module 30 (including the phase change modules 30A to 30G according to the respective modifications) can change the arrangement position of the heat receiving member 32.

1 Rack mount server system 2 Rack cabinet 3 Front door 4 Back door 5 Server module (electronic device)
6 Hard Disk Drive Device 7, 7a Cooling Fan 8 Power Supply Communication Block (Power Supply Unit)
10 Printed wiring board 20 (20a, 20b, 20c), 25 (25a, 25b, 25c) Semiconductor element (heating element)
25a, 25b, 25c Semiconductor element (heating element)
30, 30A, 30B, 30C, 30D, 30E, 30F, 30G Phase change module (boiling cooler)
31 Condenser (condenser)
31i, 33a, 33b Hollow part 31f Fin 32 (32a, 32b, 32c) Heat receiving member (boiling part)
33a, 33b Lid 34a, 34b, 34c Bottom plate 35a, 35b, 35c Boiling heat transfer part 36, 36a, 36b, 36c Connecting pipe 40 Cooling fan 50, 50A, 50B, 50C, 50D, 50E, 50F, 50G Circuit board Aliq Direction of liquid flow Ast Direction of steam flow Aair Direction of cooling air flow R Refrigerant (working fluid)
Rliq Liquid refrigerant Rst Refrigerant vapor

Claims (11)

1. A hollow portion for containing the refrigerant is formed therein, and is arranged corresponding to each of the plurality of heating elements, and receives heat from each of the heating elements to heat the refrigerant in the hollow portion. A plurality of heat receiving members;
   A condensing part for condensing and liquefying the vapor of the refrigerant heated and boiled by each of the heat receiving members;
   A plurality of connecting pipes for transporting the refrigerant,
   The plurality of connecting pipes are an upstream connecting pipe that connects the condensing part, which is an upstream part of the flow of the liquefied refrigerant, and the heat receiving member in the immediate vicinity thereof, and other downstream than the other upstream connecting pipes. It is a downstream side connecting pipe that connects the heat receiving members arranged on the side,
   Each of the upstream connecting pipe and the downstream connecting pipe has a single pipe structure.
2. The boiling cooling device according to claim 1,
   The boiling cooling apparatus according to claim 1, wherein the plurality of connecting pipes have a higher flatness as the connecting pipe is closer to the condensing part.
3. The boiling cooling device according to claim 1,
   Each of the heat receiving members includes a boiling heat transfer portion to which heat of the heating element is transmitted inside the hollow portion,
   The boiling cooling device, wherein the height of each boiling heat transfer portion is lower as the boiling heat transfer portion of the heat receiving member is farther from the condensing portion.
4. The boiling cooling device according to claim 1,
   The boiling cooling device, wherein the height of the ceiling of the hollow portion of each heat receiving member is lower as the hollow portion of the heat receiving member is farther from the condensing portion.
5. The boiling cooling device according to claim 1,
   The boiling cooling device characterized in that the height of the bottom surface of each heat receiving member is set in accordance with the height of the upper surface of the corresponding heating element.
6. The boiling cooling device according to claim 1,
   The boiling cooling device, wherein at least one of the downstream connecting pipes is disposed so as to be inclined such that the height on the downstream side is lower than the height on the upstream side.
7. The boiling cooling device according to claim 1,
   A boiling cooling device comprising a plurality of refrigerant transport paths in which the upstream connection pipe and the downstream connection pipe are combined.
8. The boiling cooling device according to claim 1,
   A plurality of the connecting pipes are arranged so as to extend in the same direction in a top view.
9. The boiling cooling device according to claim 1,
   A plurality of the connecting pipes are arranged so as to extend in different directions when viewed from above, and a boiling cooling apparatus characterized in that
10. A circuit board on which a plurality of semiconductor elements as heating elements and a boiling cooling device for cooling the semiconductor elements are mounted;
    A cooling fan for blowing air to the boiling cooling device;
    A power supply for supplying power to the cooling fan,
    The boiling cooling device is
    A hollow portion for accommodating a refrigerant is formed therein, and is disposed corresponding to each of the plurality of semiconductor elements, and receives the heat from each of the semiconductor elements to heat the refrigerant in the hollow section. A plurality of heat receiving members,
    A condensing part for condensing and liquefying the vapor of the refrigerant heated and boiled by each of the heat receiving members;
    A plurality of connecting pipes for transporting the refrigerant,
    The plurality of connecting pipes are an upstream connecting pipe that connects the condensing part, which is an upstream part of the flow of the liquefied refrigerant, and the heat receiving member in the immediate vicinity thereof, and other downstream than the other upstream connecting pipes. It is a downstream side connecting pipe that connects the heat receiving members arranged on the side,
    The electronic device according to claim 1, wherein each of the upstream side connecting pipe and the downstream side connecting pipe has a single pipe structure.
11. The electronic device according to claim 10.
    The electronic device, wherein the circuit board is mounted with a plurality of the semiconductor elements having different one or both of the height of the upper surface and the shape of the upper surface.

Images