Electronic device

Abstract

This electronic device comprises: a circuit board on which an electronic component is mounted; a housing that is fixed on a main surface of the circuit board so as to cover a mounting position of the electronic component and constitutes a storage chamber for storing a liquid refrigerant between the housing and the circuit board; and a cooling water passage that constitutes the housing together with the storage chamber and allows, to flow therethrough, cooling water for cooling a boiled refrigerant obtained by boiling the liquid refrigerant by heat generation of the electronic component immersed in the liquid refrigerant in the storage chamber.

Description

Electronic device

[0001] The present invention relates to an electronic device.

[0002] As a technology related to an electronic device using an immersion boiling cooling method in which an electronic component as a heating element is boiled and cooled in a refrigerant liquid, there is a technology described in Patent Document 1 below. In this Patent Document 1, it is described that "in an electric device 1 including a housing 10 having an internal sealed space CS, a liquid refrigerant 20L stored inside the housing 10, and at least one heating component 30 immersed in the liquid refrigerant 20L and generating heat by energization, a vapor space GS is formed above the liquid refrigerant 20L inside the housing 10, where the vaporized refrigerant 20G obtained by vaporizing the liquid refrigerant 20L due to the heat generated by the heating component 30 is released, and a heat exchange mechanism 50 that absorbs heat from the inside of the housing 10 and radiates the heat to the outside of the housing 10 is provided on the cooling wall portion 15A of the housing 10 in contact with the vapor space GS,...", and it is also described that "the electric device 1 includes a housing 10 and a circuit board 60 arranged inside the housing 10. On the circuit board 60, the heating component 30 such as an electronic component constituting the above-described circuit is mounted."

[0003] Japanese Patent Application Laid-Open No. 2022-179901

[0004] Incidentally, in-vehicle electronic devices mounted on moving bodies such as vehicles, it is essential to ensure vibration resistance against the vibration of the moving body. For this reason, in the above-described immersion boiling cooling type electronic device, a fixing structure for suppressing the vibration of the circuit board inside the housing becomes important. In addition, in-vehicle electronic devices are also required to be miniaturized in order to reduce the mounting space for the moving body. However, the electric device (electronic device) described in the cited document requires a structure for fixing the circuit board to be provided inside the housing, which causes the housing to become larger, and thus is a factor that hinders the miniaturization of the device.

[0005] Therefore, an object of the present invention is to provide an immersion boiling cooling type electronic device that can achieve miniaturization while securely fixing a housing that stores a liquid refrigerant and a circuit board on which an electronic component immersed in the liquid refrigerant inside the housing is mounted.

[0006] To solve the above problems, for example, the configuration described in the claims is adopted. The present invention includes multiple means for solving the above problems, but one example is an electronic device comprising: a circuit board on which electronic components are mounted; a housing fixed on the main surface of the circuit board so as to cover the mounting positions of the electronic components and forming a storage chamber for storing liquid refrigerant between itself and the circuit board; and a cooling water channel which together constitutes the housing with the storage chamber and carries cooling water to cool the boiling refrigerant that has been boiled by the heat generated by the electronic components immersed in the liquid refrigerant in the storage chamber.

[0007] The present invention provides an immersion boiling cooling type electronic device that can be miniaturized while securely fixing a housing that stores liquid refrigerant and a circuit board on which electronic components are mounted and immersed in the liquid refrigerant inside the housing.

[0008] This is a diagram illustrating the configuration of the electronic device of the first embodiment. This is a perspective view showing the electronic device of modification 1 of the first embodiment. This is a cross-sectional view showing the electronic device of modification 1 of the first embodiment. This is a plan view showing the electronic device of modification 2 of the first embodiment. This is a diagram illustrating the configuration of the electronic device of the second embodiment. This is a cross-sectional view (part 1) illustrating the configuration of the electronic device of the third embodiment. This is a cross-sectional view (part 2) illustrating the configuration of the electronic device of the third embodiment. This is a diagram illustrating the replacement of a unit in the electronic device of the third embodiment. This is a cross-sectional view (part 1) illustrating the configuration of the electronic device of the fourth embodiment. This is a cross-sectional view (part 2) illustrating the configuration of the electronic device of the fourth embodiment. This is a diagram illustrating the replacement of a unit in the electronic device of the fourth embodiment. This is a plan view illustrating the stacking state of the circuit board in the electronic device of the fifth embodiment. This is a cross-sectional view (part 1) illustrating the configuration of the electronic device of the fifth embodiment. This is a cross-sectional view (part 2) illustrating the configuration of the electronic device of the fifth embodiment. This is a cross-sectional view illustrating the configuration of the electronic device of the sixth embodiment. This is a cross-sectional view illustrating the configuration of the electronic device of the seventh embodiment. This is a perspective view illustrating the configuration of the electronic device of the eighth embodiment. This is a plan view illustrating the configuration of the electronic device according to the eighth embodiment. This is a cross-sectional view illustrating the configuration of the electronic device according to the eighth embodiment. This is a cross-sectional view illustrating the configuration of the electronic device according to the ninth embodiment.

[0009] Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the drawings. In each embodiment, the same components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0010] ≪First Embodiment≫ Figure 1 is a diagram illustrating the configuration of the electronic device 1 of the first embodiment, and shows a front view (1), a cross-sectional view (2) of the front view (1) along line A-A, and a cross-sectional view (3) of the front view (1) along line B-B. The electronic device 1 shown in Figure 1 is, for example, an in-vehicle electronic control device for controlling an automobile, and is an immersion boiling cooling type electronic device installed inside the vehicle. This electronic device 1 comprises a circuit board 10, a housing 20, and a sealing member 30, and is installed inside the automobile in a predetermined state with the main surface of the circuit board 10 facing approximately vertically (z direction in the drawing).

[0011] In the following, the configuration of the electronic device 1 will be described assuming that the electronic device 1 is arranged in the predetermined state described above. In the drawings used in the description of each embodiment thereafter, the horizontal direction along the main surface of the circuit board 10 when the electronic device 1 is arranged in the predetermined state described above will be defined as the x-direction. Furthermore, the direction perpendicular to the z-direction and the x-direction, and the direction in which the circuit board 10 and the housing 20 are stacked will be defined as the y-direction. The configuration of each component constituting the electronic device 1 will be described below.

[0012] <Circuit board 10> The circuit board 10 may be, for example, a general multilayer wiring board, in which a surface wiring pattern is provided on the main surface of the substrate and an inner layer wiring pattern is provided inside the substrate. Such a circuit board 10 has electronic components 11 and connectors 12 mounted on a roughly rectangular main surface.

[0013] Among these, the electronic components 11 are computing elements such as a CPU (Central Processing Unit) and semiconductor elements such as memory, and they generate heat when the circuit operates. Such electronic components 11 are mounted near the center of the circuit board 10. The connector 12 is used to connect the electronic components 11 mounted on the circuit board 10 to external devices and is mounted at the edge of the circuit board 10. Here, as an example, a configuration in which the connector 12 is mounted at the lower end in the z direction of the circuit board 10 is illustrated. The connector 12 is connected to the electronic components 11 via the inner layer wiring pattern of the circuit board 10.

[0014] In Figure 1, the electronic component 11 and connector 12 are shown mounted on one main surface of the circuit board 10. However, the electronic component 11 and connector 12 may be mounted on both main surfaces of the circuit board 10. Furthermore, the electronic component 11 and connector 12 may be mounted on different main surfaces of the circuit board 10.

[0015] <Housing 20> The housing 20 houses the electronic components 11 mounted on the circuit board 10 and also serves to fix the circuit board 10 in place. It also stores a liquid coolant L1 for cooling the housed electronic components 11. The housing 20 also leaves the connectors 12 mounted on the circuit board 10 exposed without housing them. Such a housing 20 is positioned so that at least a part of it rests on the main surfaces on both sides of the circuit board 10. In this electronic device 1, two housings 20 are arranged so as to sandwich the circuit board 10, forming the external shape of the electronic device 1.

[0016] Each housing 20 is made of a metal material such as aluminum, or a resin material with good thermal conductivity. Such a housing 20 is equipped with a storage chamber 21 for storing liquid refrigerant L1 and a cooling water channel 22 for passing cooling water L2, and is connected to two housings 20 by a connecting pipe 23 that connects the cooling water channels 22 of the two housings 20. In addition, each housing 20 is equipped with either a cooling water supply pipe 24 or a cooling water discharge pipe 25 for the cooling water L2.

[0017] [Storage Chamber 21] The storage chamber 21 is a recessed portion that covers the main surface of the circuit board 10, and the recessed portion of the housing 20 constitutes the storage chamber 21 that stores liquid refrigerant L1 between itself and the circuit board 10. Such a storage chamber 21 is placed on the main surface of the circuit board 10. The circuit board 10 is fixed to the housing 20 by joining the periphery of such a storage chamber 21 to the main surface of the circuit board 10. The storage chamber 21 also covers at least the mounting positions of the electronic components 11 on the circuit board 10, and preferably has a size that surrounds the area where the surface wiring pattern is laid on the main surface of the circuit board 10. This prevents the uneven shape of the main surface of the circuit board 10 caused by the laying of the surface wiring pattern from affecting the adhesion between the periphery of the storage chamber 21 and the circuit board 10.

[0018] Note that in the front view (1) and the A-A cross-sectional view (2) of Figure 1, the circuit board 10 is shown protruding from the periphery of the housing 20. However, if the storage chamber 21 of the housing 20 is placed on the main surface of the circuit board 10, the width of the storage chamber 21 in the x-direction may be approximately the same as the width of the circuit board 10 in the x-direction.

[0019] Such a storage chamber 21 is positioned so that its peripheral edge abuts the main surface of the circuit board 10, forming a space between it and the circuit board 10. When the electronic device 1 is installed in a predetermined state with the circuit board 10 in a substantially vertical direction (z direction in the drawing), the storage chamber 21 stores liquid refrigerant L1 in the space formed between it and the circuit board 10. As a result, the electronic components 11 and the mounting position of the electronic components 11 are immersed in the liquid refrigerant L1.

[0020] Here, the liquid refrigerant L1 is defined as an insulating material with a boiling point lower than the heat resistance temperature of the electronic component 11. When multiple electronic components 11 with different heat resistance temperatures are mounted on the circuit board 10, the liquid refrigerant L1 is defined as a material with a boiling point lower than the lowest heat resistance temperature. Examples of such liquid refrigerants L1 include fluorine-based inert liquids such as perfluoropolyether (PFPE), perfluorocarbon (PFC), hydrofluoroether (HFE), and silicone oil.

[0021] The amount of liquid refrigerant L1 stored in the storage chamber 21 is adjusted so that when the electronic device 1 is installed in a predetermined state, a gas phase space 21s is formed in the upper part of the storage chamber 21, and preferably the electronic components 11 mounted on the circuit board 10 and their mounting positions are sufficiently immersed. As a result, the liquid refrigerant L1 is heated by the heat generated by the electronic components 11, and the boiling refrigerant G1 (shown only in the B-B cross-sectional view (3)) that results from the heating of the liquid refrigerant L1 is released into the gas phase space 21s in the upper part of the storage chamber 21.

[0022] In the B-B cross-sectional view (3), the housings 20 on both sides of the circuit board 10 are of the same shape, thus increasing the versatility of the housings 20. However, the housing 20 located on the side where the connector 12 is not mounted may have its storage chamber 21 extended in the z direction to a position overlapping with the connector 12, thereby increasing the amount of liquid refrigerant L1 stored and enhancing the cooling effect.

[0023] [Cooling water channel 22] The cooling water channel 22 is located above the storage chamber 21 and extends in the x direction to cover the upper part of the storage chamber 21. When the electronic device 1 is installed in a predetermined state, it carries cooling water L2 to cool the boiling refrigerant G1 released into the gas phase space 21s. Such a cooling water channel 22 is integrally formed with the storage chamber 21 and may be tubular in shape, or a U-shaped pipe with its opening covered by a lid, as long as it is a shape that allows cooling water L2 to pass through.

[0024] Here, the boiling refrigerant G1 released into the gas phase space 21s is cooled by heat exchange with the cooling water L2 in the cooling water channel 22 to become condensed refrigerant L1', and returns to liquid refrigerant L1. The immersion boiling cooling method electronic device 1 dissipates the heat generated by the electronic components 11 to the cooling water L2 by repeatedly boiling and condensing the liquid refrigerant L1 as described above, thereby releasing the heat to the outside of the device.

[0025] In such an immersion boiling cooling electronic device 1, in order to efficiently cool the boiling refrigerant G1 in the cooling water channel 22, it is preferable that the cooling water channel 22 be arranged such that the gas phase space 21s from which the boiling refrigerant G1 is released is wider, and the heat exchange area between the cooling water channel 22 and the boiling refrigerant G1 is wider. Such a cooling water channel 22 has a configuration in which the distance between the wall portion facing the storage chamber 21 and the main surface of the circuit board 10 is gradually widened toward the storage chamber.

[0026] Furthermore, in the cooling water channel 22, it is preferable to widen the gas phase space 21s by narrowing the portion of the wall facing the circuit board 10 that protrudes toward the circuit board 10 in the z direction. However, a portion of the wall facing the circuit board 10 in the cooling water channel 22 will be a portion that is joined to the main surface of the circuit board 10 and fixes the circuit board 10, and will therefore have a shape that protrudes toward the circuit board 10. In this case, for example, the length h extending toward the liquid refrigerant L1 storage portion below the protruding step t is made larger than the protruding step t in the thickness direction of the circuit board 10.

[0027] [Connecting pipe 23] The connecting pipe 23 connects the cooling water passages 22 provided in the two housings 20. Such a connecting pipe 23 is located at the top of the circuit board 10 in the z direction and is provided to communicate with the two cooling water passages 22 at one end of the cooling water passage 22. In order to accommodate this connecting pipe 23, the cooling water passages 22 are arranged to extend above the circuit board 10 in the z direction.

[0028] [Supply pipe 24 and discharge pipe 25] The supply pipe 24 supplies cooling water L2 to one of the two cooling water channels 22. The cooling water L2 supplied from the supply pipe 24 is cooled to a temperature sufficiently lower than the boiling point of the liquid refrigerant L1 in a heat exchange engine (not shown) located outside the electronic device 1. As shown by the arrow in the cross-sectional view (2) along line A-A, the cooling water L2 supplied from the supply pipe 24 to one of the cooling water channels 22 is supplied to the other cooling water channel 22 via the connecting pipe 23.

[0029] The discharge pipe 25 discharges the cooling water L2 from the other of the two cooling water channels 22. The cooling water L2 discharged from the discharge pipe 25 is returned to the heat exchange engine by a pump (not shown) located outside the electronic device 1, and the cooling water L2 circulates between the heat exchange engine and the two cooling water channels 22.

[0030] Furthermore, these supply pipes 24 and discharge pipes 25 are connected to the respective cooling water channels 22 at the end opposite to the connecting pipe 23. In this case, as shown by the arrows in the A-A cross-sectional view (2), the cooling water L2 supplied from the supply pipe 24 flows from one end of the cooling water channel 22 to the opposite end, passes through the connecting pipe 23, and flows from the other end of the cooling water channel 22 to the opposite end, and is discharged from the discharge pipe 25. This prevents the stagnation of cooling water L2 within the cooling water channels 22.

[0031] <Sealing Member 30> The sealing member 30 is inserted between the main surfaces on both sides of the circuit board 10 and the housing 20, fixing the circuit board 10 to the housing 20 and shielding the space between the circuit board 10 and the storage chamber 21 of each housing 20 from the surroundings, thereby sealing it. At a minimum, when the electronic device 1 is installed in a predetermined state, the sealing member 30 seals the storage chamber 21 so that the liquid refrigerant L1 does not leak out of the storage chamber 21, and more preferably completely seals the storage chamber 21 so that it is completely isolated from the outside.

[0032] Such a sealing member 30 is continuously arranged between the main surface of the circuit board 10 and the outer wall of the cooling water channel 22 on the circuit board 10 side, extending from the periphery of the storage chamber 21 in the housing 20, thereby sealing the storage chamber 21. Here, it is preferable that the storage chamber 21 is sized to surround the area where the surface wiring pattern is laid on the main surface of the circuit board 10. In this case, the sealing member 30 is continuously arranged on both main surfaces of the circuit board 10 without being affected by the unevenness of the main surface of the circuit board 10 caused by the laying of the surface wiring pattern.

[0033] Furthermore, if the storage chamber 21 is completely sealed, the gas phase space 21s within the storage chamber 21 may be in a low-pressure state such as a vacuum. This allows the boiling refrigerant G1 released into the gas phase space 21s to be efficiently cooled in the cooling water channel 22 without being hindered by residual air.

[0034] <Effects of the First Embodiment> The electronic device 1 of the first embodiment described above has a configuration in which the periphery of the liquid refrigerant L1 storage chamber 21 in the housing 20 is fixed to the main surface of the circuit board 10, and the liquid refrigerant L1 is stored between the circuit board 10 and the storage chamber 21. This makes it possible to miniaturize the housing 20 while ensuring that the circuit board 10 is fixed to the housing 20 in the immersion boiling cooling type electronic device 1.

[0035] <Modification 1> In the first embodiment described above with reference to Figure 1, it was preferable that the storage chamber 21 be sized to surround the area where the surface wiring pattern provided on the main surface of the circuit board 10 is laid. However, the surface wiring pattern of the circuit board 10 may be positioned in contact with the periphery of the storage chamber 21.

[0036] Figure 2 is a perspective view showing the electronic device 1-1 of Modification 1 of the first embodiment, and is a diagram showing the layout when the surface wiring pattern 102 is placed on the main surface of the circuit board 10 at a position that abuts the periphery of the storage chamber 21. Figure 3 is a cross-sectional view showing the electronic device 1-1 of Modification 1 of the first embodiment, and is a cross-sectional view taken along line A-A in Figure 2.

[0037] As shown in these figures, the circuit board 10 has a base material 101 and a surface wiring pattern 102 provided on its main surface, and the base material 101 also has an inner layer wiring pattern which is not shown here. In Figures 2 and 3, only the peripheral wiring pattern 102a, which is positioned to abut the periphery of the storage chamber 21, is shown, but in addition to the peripheral wiring pattern 102a, other surface wiring patterns 102 are also arranged on the main surface of the base material 101.

[0038] Here, the peripheral wiring pattern 102a surrounds the electronic component 11 and is laid continuously without interruption as a base for the sealing member 30 at a position corresponding to the periphery of the storage chamber 21. Such a peripheral wiring pattern 102a functions, for example, as ground wiring.

[0039] In this modified configuration 1, the peripheral wiring pattern 102a, which is part of the surface wiring pattern 102, is continuously arranged around the entire circumference between the circuit board 10 and the housing 20 including the storage chamber 21. Therefore, it is possible to prevent the uneven shape of the main surface of the circuit board 10 caused by the laying of the surface wiring pattern 102 from affecting the adhesion between the periphery of the storage chamber 21 and the circuit board 10.

[0040] <Modification 2> In the first embodiment described using Figure 1, a configuration was described in which the connector 12 is mounted on the lower end of the circuit board 10 in the z direction. However, the mounting position of the connector 12 is not limited to the lower end of the circuit board 10 in the z direction, but is possible as long as it is a portion of the circuit board 10 that extends to the outside of the housing 20. Figure 4 is a plan view showing the electronic device 1-2 of modification 2 of the first embodiment. As shown in Figure 4, the connector 12 may also be mounted on the end of the circuit board 10 in the x direction, and the same effects as in the first embodiment can be obtained.

[0041] Note that the x-direction is the horizontal direction along the main surface of the circuit board 10 when the electronic device 1-2 is positioned in a predetermined state. This modified example 2 can also be configured in combination with modified example 1.

[0042] ≪Second Embodiment≫ Figure 5 is a diagram illustrating the configuration of the electronic device 2 of the second embodiment, showing a front view (1), a cross-sectional view (2) of front view (1) along A-A, a cross-sectional view (3) of front view (1) along B-B, and a cross-sectional view (3') of front view (1) along B-B'. The differences between the electronic device 2 of the second embodiment shown in these figures and the electronic device 1 of the first embodiment are the shape of the main surface of the circuit board 10' and the shape of the deformed waterway 22' in the housing 20. The other configurations are the same as in the first embodiment, so a redundant explanation is omitted here.

[0043] <Circuit board 10'> The circuit board 10' has a planar shape with the upper end portion on the main surface being cut out, which is substantially rectangular. The circuit board 10' has a planar shape with a portion corresponding to the communication pipe 23 connecting the deformed water channels 22' of the two housings 20 cut out, and the communication pipe 23 is arranged in the cut-out portion. That is, the circuit board 10' extends to the same height as the communication pipe 23 in the z direction at a position shifted from the communication pipe 23 in the x direction. Such a circuit board 10' is fixed to the two housings 20 by seal members 30 arranged along the peripheral edges of both main surfaces.

[0044] In this case, the seal member 30 is continuously arranged between the main surface of the circuit board 10' from the periphery of the storage chamber 21 in the housing 20 to the outer wall on the circuit board-side of the deformed water channel 22', and making the storage chamber 21 airtight is the same as in the first embodiment.

[0045] <Housing 20> The housing 20 includes a storage chamber 21 for storing the liquid refrigerant L1, a deformed water channel 22' for passing the cooling water L2, a communication pipe 23 for connecting the cooling water channels 22 of the two housings 20, a supply pipe 24 for the cooling water L2, and a discharge pipe 25 for the cooling water L2, which is the same as in the first embodiment. Among these, the deformed water channel 22' has the following shape.

[0046] [Deformed water channel 22'] The deformed water channel 22' is arranged in the x direction above the storage chamber 21, and when the electronic device 1 is installed in a predetermined state, the cooling water L2 for cooling the boiling refrigerant G1 released into the gas-phase space 21s passes through it. It is preferable that this deformed water channel 22' has a configuration in which the gas-phase space 21s is widened by narrowing the portion protruding toward the circuit board 10', which is the same as in the first embodiment.

[0047] Here, the circuit board 10' has a planar shape with its upper end portion cut out, and at a position offset from the communication pipe 23 in the x direction, it extends to the same height as the communication pipe 23 in the z direction. Therefore, at a position offset from the communication pipe 23 in the x direction, the joining position between the circuit board 10' and the housing 20 via the sealing member 30 can be set at a higher position in the z direction than the communication pipe 23. As a result, at a position offset from the communication pipe 23 in the x direction, the distance between the wall portion facing the circuit board 10' side of the deformed water channel 22' and the circuit board 10' can be widened.

[0048] That is, in the B - B cross-sectional view (3) passing through the communication pipe 23, the length h' in the B - B cross-sectional view (3') passing through a position deviated from the communication pipe 23 can be made larger than the length h of the lower part of the protruding step t facing the circuit board 10' side of the deformed water channel 22'. As a result, the cooling area of the boiling refrigerant G1 can be widened. Also, as a result, a configuration is provided in which the gas phase space 21s in the storage chamber 21 can be made wider than in the first embodiment.

[0049] <Effect of the Second Embodiment> As described above, according to the second embodiment, since the cooling area of the boiling refrigerant G1 can be widened and the gas phase space 21s in the storage chamber 21 can be made wider, it is possible to improve the cooling efficiency of the boiling refrigerant G1. Moreover, since the area of the housing 20 extending in the z direction is reduced compared to the circuit board 10', the electronic device 2 can be miniaturized. Note that this second embodiment can be combined with Modification Example 1 and Modification Example 2 of the first embodiment.

[0050] ≪Third Embodiment≫ Figures 6 and 7 are cross-sectional views (part 1) and (part 2) illustrating the configuration of the electronic device 3 of the third embodiment. The electronic device 3 of the third embodiment shown in these figures is configured such that the electronic device 1 (see Figure 1) described in the first embodiment is used as one unit 1a, and multiple units 1a are stacked and connected in a direction perpendicular to the main surface of the circuit board 10 (y direction). The circuit boards 10 mounted on each unit 1a may have the same function or may have different functions. Adjacent units 1a are connected by unit connecting pipes 301 (shown only in Figure 7). Figures 6 and 7 are x-y and z-y cross-sectional views when the electronic device 3 is arranged in a predetermined state with the main surface of the circuit board 10 in a substantially vertical direction (z direction in the drawing).

[0051] <Unit Connecting Pipe 301> The unit connecting pipe 301 connects the cooling water channels 22 of adjacent housings 20 in each unit 1a, thereby connecting adjacent units 1a. Such a unit connecting pipe 301 is positioned at approximately the same height in the z direction as the connecting pipe 23 for connecting the cooling water channels 22 within each unit 1a, and at the opposite end in the x direction.

[0052] In the electronic device 3 with this configuration, the supply pipe 24 and the discharge pipe 25 are connected to two cooling water channels 22 located on both sides in the stacking direction (y-direction) of the unit 1a. As in the first embodiment, these supply pipes 24 and discharge pipes 25 are connected to each cooling water channel 22 at the end opposite to the connecting pipe 23. The unit connecting pipe 301 connects the cooling water channels 22 of adjacent housings 20 at the end in the same direction as the supply pipe 24 and the discharge pipe 25.

[0053] As a result, as shown by the arrows in Figure 6, the cooling water L2 supplied from the supply pipe 24 to the cooling water channel 22 located at one end flows from one end of the cooling water channel 22 to the other end and passes through the connecting pipe 23. The cooling water L2 that has passed through the connecting pipe 23 flows from one end of the adjacent cooling water channel 22 to the other end, passes through the unit connecting pipe 301, is supplied to the end of the adjacent cooling water channel 22, and is discharged from the discharge pipe 25 connected to the cooling water channel 22 located at the other end without being divided. This prevents the accumulation of cooling water L2 within the cooling water channel 22. In addition, since the cooling water L2 is not divided, the flow rate and velocity of the cooling water L2 in the cooling water channel 22 can be increased, improving the cooling performance.

[0054] <Unit Replacement> Figure 8 is a diagram illustrating the replacement of unit 1a in the electronic device 3 of the third embodiment. As shown in Figure 8, if some of the multiple units 1a constituting the electronic device 3 fail, for example, if it is the middle unit 1a, the connection between the units 1a by the unit connecting pipe 301 is disconnected, and only the failed middle unit 1a is removed and replaced. In this case, the cooling water in the cooling water passage 22 is drained before performing the replacement work.

[0055] <Effects of the Third Embodiment> The electronic device 3 of the third embodiment has a structure in which unitized electronic devices 1 are stacked, making it possible to easily increase functionality simply by increasing the number of units. In addition, if a malfunction occurs in a specific circuit board 10, only the unit 1a containing that circuit board 10 needs to be removed and replaced, making maintenance easy and reducing costs.

[0056] In the third embodiment described above, each unit 1a has a circuit board 10 with a connector 12 mounted on its lower part in the z direction. However, some or all of the multiple units 1a may be configured to use a circuit board 10 with a connector 12 mounted on its end in the x direction, as shown in Modification 2 of the first embodiment.

[0057] Furthermore, this third embodiment can be combined with the second embodiment. In this case, the electronic device 2 of the second embodiment described with reference to Figure 5 can be treated as a single unit, and multiple units can be stacked perpendicular to the main surface of the circuit board 10 (y-direction), with adjacent units connected by unit connecting tubes.

[0058] ≪Fourth Embodiment≫ Figures 9 and 10 are cross-sectional views (part 1) and (part 2) illustrating the configuration of the electronic device 4 of the fourth embodiment. The electronic device 4 of the fourth embodiment shown in these figures is a modified version of the third embodiment, and has a common housing 20b formed by stacking units 1b, each of which a single circuit board 10 is sandwiched between housings, in a direction perpendicular to the main surface of the circuit board 10 (y direction), and integrating them between adjacent units 1b. Figures 9 and 10 are x-y and z-y cross-sectional views, respectively, when the electronic device 4 is arranged in a predetermined state with the main surface of the circuit board 10 in a substantially vertical direction (z direction in the drawing).

[0059] In this electronic device 4, the two housings 20 arranged on both sides of the stacking direction of unit 1b have the same configuration as the housing 20 described in the first embodiment above. Therefore, the configuration of the common housing 20b will be described below. Each unit 1b includes one circuit board 10, and both main surfaces of the circuit board 10 are fixed to the housing 20 or the common housing 20b.

[0060] <Common enclosure 20b> The common enclosure 20b is formed by integrating the enclosures of adjacent units 1b. Therefore, adjacent units 1b are connected by the common enclosure 20b. Similar to enclosure 20, the common enclosure 20b houses the electronic components 11 mounted on the circuit board 10 and stores the liquid coolant L1 for cooling the housed electronic components 11.

[0061] The common housing 20b has storage chambers 21 for storing liquid refrigerant L1 on both sides facing the circuit boards 10 of adjacent units 1b, and is also equipped with a common waterway 22b for passing cooling water L2. Of these, each storage chamber 21 is the same as that of other embodiments having storage chambers, and the only difference is that the adjacent units 1b share a wall, so a detailed explanation is omitted here.

[0062] [Common water channel 22b] The common water channel 22b is configured as a cooling water channel shared between adjacent units 1b, and is formed by combining and integrating the adjacent cooling water channels 22 (see Figures 6 and 7) in the electronic device 3 of the third embodiment described above. For this reason, this electronic device 4 does not require the unit connecting pipe 301 that was necessary in the electronic device 3 of the third embodiment to connect the cooling water channels 22 in adjacent units 1a.

[0063] Furthermore, within each unit 1b of this electronic device 4, the cooling water channels 22 and common channels 22b, which are located on both sides of the circuit board 10, and the common channels 22b themselves are connected by connecting pipes 23. In addition, supply pipes 24 and discharge pipes 25 for cooling water L2 are connected to the ends of the cooling water channels 22, which are located on both sides of the stacking direction of the circuit board 10. These connecting pipes 23, supply pipes 24, and discharge pipes 25 are arranged so that the cooling water L2 supplied from the supply pipe 24 flows from one end to the other of each cooling water channel 22 and common channel 22b without being divided and is discharged from the discharge pipe 25.

[0064] <Unit Replacement> Figure 11 is a diagram illustrating the replacement of unit 1b in the electronic device 4 of the fourth embodiment. As shown in Figure 11, if some of the multiple units 1b constituting the electronic device 4 fail, for example, if it is the middle unit 1b, the connection between the common water channels 22b by the connecting pipe 23 is disconnected. The circuit board 10 of the failed middle unit 1b is removed from the common housing 20b and replaced with the circuit board 10 of the failed unit 1b. In this case, the cooling water in the cooling water channel 22 and the common water channel 22b, as well as the liquid refrigerant L1 of the failed unit 1b, are drained before the replacement work is carried out.

[0065] <Effects of the Fourth Embodiment> The electronic device 4 of the fourth embodiment described above can obtain the same effects as the electronic device 3 of the third embodiment, and furthermore, by using a common housing 20b with an integrated housing, the number of parts is reduced and the device is made smaller.

[0066] ≪Fifth Embodiment≫ Figures 12 to 14 are diagrams illustrating the configuration of the electronic device 5 of the fifth embodiment. Figure 12 is a plan view illustrating the stacked state of the circuit board 10' in the electronic device 5 of the fifth embodiment. Figures 13 and 14 are cross-sectional views (part 1) and (part 2) illustrating the configuration of the electronic device 5 of the fifth embodiment, and are z-y cross-sectional views when the electronic device 5 is arranged in a predetermined state with the main surface of the circuit board 10' in a substantially vertical direction (z direction on the drawing). Figure 13 corresponds to the B-B cross-section of Figure 12, and Figure 14 corresponds to the B'-B' cross-section of Figure 12.

[0067] The electronic device 5 of the fifth embodiment shown in these figures is a modified version of the electronic device 4 of the fourth embodiment (see Figures 9 to 11), and is a configuration that combines the fourth and second embodiments. In this electronic device 5, the electronic device 2 described in the second embodiment (see Figure 5) is used as one unit 2b, and multiple units 2b are stacked perpendicular to the main surface of the circuit board 10' (y-direction), with adjacent units 2b sharing a common housing 20b. Note that the circuit boards 10' mounted on each unit 2b may have the same function or may have different functions.

[0068] The differences between this fifth embodiment of the electronic device 5 and the fourth embodiment of the electronic device 4 (see Figures 9 to 11) lie in the configuration of the circuit board 10', the deformed water channels 22' of the housings 20 on both sides of the stacking direction of the circuit board 10', and the deformed common water channel 22b' of the common housing 20b. The other configurations are the same as those of the fourth embodiment, so their explanation is omitted here.

[0069] <Circuit board 10'> The circuit board 10' is the same as that described in the second embodiment, and has a planar shape in which the upper end of the main surface, which is substantially rectangular in shape, is cut out. However, as shown in Figure 12, each unit 2b is stacked such that the cutouts of the circuit board 10' are alternately arranged at both ends in the x direction.

[0070] <Housing 20> [Deformed water channels 22'] The deformed water channels 22' in the housing 20 on both sides in the stacking direction of the circuit board 10' are the same as the deformed water channels 22' of the housing 20 in the second embodiment described with reference to Figure 5.

[0071] <Common Housing 20b> [Deformed Common Waterway 22b'] The deformed common waterway 22b' of the common housing 20b is configured as a waterway shared between adjacent units 2b, and when the electronic device 2 of the second embodiment is stacked as is, adjacent deformed waterways 22' are combined. Furthermore, within each unit 2b, the deformed waterways 22' and the deformed common waterway 22b', which are located on both sides of the circuit board 10', and the deformed common waterways 22b' themselves are connected by a connecting pipe 23. As a result, in the deformed common waterway 22b', at a position offset from the connecting pipe 23 in the x direction, the joining position between the circuit board 10' and the common housing 20b via the sealing member 30 can be made higher in the z direction than the connecting pipe 23. This makes it possible to widen the gap between the wall portion of the deformed common waterway 22b' facing the circuit board 10' and the circuit board 10' at a position offset from the connecting pipe 23 in the x direction.

[0072] Therefore, as shown in Figure 13, in the deformed common waterway 22b', the lengths h, h' of the lower part of the protruding step t toward the circuit board 10' can be made larger than the similar length h' at a position away from the connecting pipe 23. This makes it possible to increase the cooling area of ​​the boiling refrigerant G1, and as a result, the gas phase space 21s in the storage chamber 21 can be made wider than in the fourth embodiment.

[0073] Furthermore, supply pipes 24 and discharge pipes 25 for cooling water L2 are connected to the ends of each deformed water channel 22', which is located on both sides of the stacking direction of the circuit board 10'. These supply pipes 24 and discharge pipes 25 and the connecting pipe 23 are arranged so that the cooling water L2 supplied from the supply pipe 24 flows from one end to the other of each deformed water channel 22' and deformed common water channel 22b' without being divided and is discharged from the discharge pipe 25.

[0074] <Effects of the Fifth Embodiment> The electronic device 5 of the fifth embodiment described above can obtain the same effects as the electronic device 4 of the fourth embodiment. In addition, it can increase the cooling area of ​​the boiling refrigerant G1 and widen the gas phase space 21s in the storage chamber 21, thereby improving the cooling efficiency of the boiling refrigerant G1. Furthermore, since the area of ​​the housing 20 extending in the z direction from the circuit board 10' is reduced, it can be made smaller than the electronic device 4 of the fourth embodiment.

[0075] ≪Sixth Embodiment≫ Figure 15 is a cross-sectional view illustrating the configuration of the electronic device 6 of the sixth embodiment. The electronic device 6 of the sixth embodiment shown in Figure 15 is a modified version of the electronic device 5 of the fifth embodiment (see Figures 12 to 14), and differs from that of the fifth embodiment in that the circuit board 10' has through holes 10h and the common housing 20b has through holes 20h. The other configurations are the same as those of the fifth embodiment.

[0076] At least one through-hole 10h in the circuit board 10' is located in a part that does not affect the wiring pattern of the circuit board 10'. Also, at least one through-hole 20h in the common housing 20b is located in a position sandwiched between the two storage chambers 21, excluding the deformed common waterway 22b'. Preferably, these through-holes 10h, 201 are provided in a position where they are immersed in the liquid refrigerant L1 and a position where they are exposed to the gas phase space 21s above them.

[0077] <Effects of the Sixth Embodiment> The electronic device 6 of the sixth embodiment described above allows the liquid refrigerant L1 and boiling refrigerant G1 to flow between the housing 20 and the common housing 20b, and between the common housings 20b themselves, through the through-holes 10h of the circuit board 10'. Similarly, the liquid refrigerant L1 and boiling refrigerant G1 can flow between the units 2b through the through-holes 20h of the common housing 20b. As a result, even if the amount of heat generated by the electronic components 11 mounted on each circuit board 10' differs, and the boiling state of the liquid refrigerant L1 differs for each unit 2b, the flow of the liquid refrigerant L1 and boiling refrigerant G1 can eliminate this difference and efficiently cool the electronic components 11.

[0078] In the sixth embodiment described above, through holes may be provided in only one of the circuit board 10' and the common housing 20b. Furthermore, this sixth embodiment can be combined with the fourth embodiment described using Figures 9 to 11. In this case, through holes are provided in at least one of the circuit board 10' and the common housing 20b of the electronic device 4 of the fourth embodiment. Also, in this sixth embodiment, the configuration in which through holes 10h are provided in the circuit board 10' can be combined with all other embodiments.

[0079] <<Seventh Embodiment>> Figure 16 is a cross-sectional view illustrating the configuration of the electronic device 7 of the seventh embodiment. The electronic device 7 of the seventh embodiment shown in Figure 16 is a modified version of the electronic device 4 of the fourth embodiment (see Figures 9 to 11). This electronic device 7 has a configuration in which a connecting pipe 23 connecting the cooling water channel 22 and the common water channel 22b, and a connecting pipe 23 connecting the common water channels 22b to each other are provided at both ends of the cooling water channel 22 and the common water channel 22b within a single unit 1b. The other configurations are the same as in the fourth embodiment.

[0080] <Effects of the Seventh Embodiment> According to the electronic device 7 of the seventh embodiment with this configuration, the cooling water L2 supplied from the supply pipe 24 to one end of the cooling water channel 22 is divided into two directions: one towards the opposite end of the cooling water channel 22 and the other towards the common water channel 22b via the connecting pipe 23. Furthermore, the cooling water L2 is divided into two directions as it passes through each connecting pipe 23, and then merges at the discharge pipe 25 before being discharged. As a result, compared to the electronic device 4 of the fourth embodiment (see Figures 9 to 11), it is possible to reduce the pressure loss of the cooling water L2 and to reduce the capacity of the circulation pump for circulating the cooling water L2.

[0081] Furthermore, this seventh embodiment may be combined with a configuration in which the cooling water L2 is not diverted, by changing the arrangement of the connecting pipe 23, taking into consideration the cooling performance by the cooling water L2 and the performance of the circulation pump.

[0082] This seventh embodiment can be combined with the third embodiment described using Figures 6 to 8. In this case, the cooling water channels 22 can be connected at both ends using the connecting pipe 23 and the unit connecting pipe 301. This seventh embodiment can also be combined with the fifth embodiment described using Figures 12 to 14. In this case, the circuit board is configured with notches at the upper ends on both sides. This makes it possible to provide connecting pipes 23 that connect the deformed water channel 22' and the deformed common water channel 22b', and connecting pipes 23 that connect the deformed common water channels 22b' to each other, at both ends of the deformed water channel 22' and the deformed common water channel 22b'.

[0083] ≪Eighth Embodiment≫ Figures 17 to 19 are perspective views, plan views, and cross-sectional views illustrating the configuration of the electronic device 8 of the eighth embodiment. The cross-sectional view in Figure 19 corresponds to the B-B section in the plan view of Figure 18. The electronic device 8 shown in these figures is a modified version of the electronic device 5 of the fifth embodiment (see Figures 12 to 14). This electronic device 8 is characterized by the shape of the storage chamber 21' located on the side where the connector 12 is mounted, and since the other configurations are the same as in the fifth embodiment, their explanation will be omitted.

[0084] <Storage Chamber 21'> The storage chamber 21' located on the side where the connector 12 is mounted has a planar shape that surrounds the connector 12 along the connector 12 mounted on the circuit board 10'. For example, as shown in Figure 18, if the connector 12 is mounted in the center of the circuit board 10' at the lower end in the z direction of the circuit board 10', the storage chamber 21' has a planar shape that extends in the z direction on both sides of the connector 12. Figure 19 shows a configuration in which the connector 12 is arranged on one side of the circuit board 10' in the stacking direction, but the connector 12 may be arranged on either side of the circuit board 10', or on both sides.

[0085] Note that the storage chamber 21 (see Figure 19) located on the side of the circuit board 10' in the stacking direction where the connector 12 is not mounted may have the same shape as described in other embodiments. However, it is preferable that the storage chamber 21 located on the side where the connector 12 is not mounted is extended in the z direction to a position where it overlaps with the connector 12. This increases the amount of liquid refrigerant L1 that can be stored.

[0086] <Effects of the Eighth Embodiment> According to the electronic device 8 of this eighth embodiment, the mounting portion of the connector 12 on the circuit board 10' does not protrude from the housing 20 and the common housing 20b, making it possible to miniaturize the electronic device 8.

[0087] Furthermore, this eighth embodiment can be combined with all other embodiments, and the combined effects can be obtained.

[0088] <Ninth Embodiment> Figure 20 is a cross-sectional view illustrating the configuration of the electronic device 9 of the ninth embodiment. The difference between the electronic device 9 of the ninth embodiment shown in Figure 20 and the electronic device 1 of the first embodiment (see Figure 1) is that the housing 20 is provided only on the side of the circuit board 10 where the electronic components 11 are mounted. In this case, the supply pipe 24 and the discharge pipe 25 are connected to both ends of a single cooling water channel 22. The other configurations are the same.

[0089] <Effects of the Ninth Embodiment> Even with an electronic device 9 having such a configuration, by fixing the periphery of the liquid refrigerant L1 storage chamber 21 in the housing 20 to the main surface of the circuit board 10, and storing the liquid refrigerant L1 between the circuit board 10 and the storage chamber 21, it is possible to miniaturize the housing 20 while ensuring that the circuit board 10 is fixed to the housing 20 in the immersion boiling cooling type electronic device 1.

[0090] This ninth embodiment can be combined with other embodiments. When combined with the third embodiment described using Figures 6 to 8, the electronic devices 9 can be stacked and connected in the main surface direction (y direction) of the circuit board 10. When combined with the fourth embodiment described using Figures 9 to 11, the configuration can be made by removing the housing 20 on both sides of the circuit board 10 in the stacking direction, specifically the housing 20 on the side where the electronic components 11 are not mounted. The same applies when combined with the fifth, seventh, and eighth embodiments. When combined with the sixth embodiment described using Figure 15, the circuit board 10 that is exposed by removing one of the outermost housings 20 in the stacking direction of the circuit board 10 is one that does not have through holes 10h. In any of the above cases, a connecting pipe is connected to the adjacent cooling water channel, and a supply pipe 24 and a discharge pipe 25 are connected to the cooling water channel of the outermost housing 20 in the stacking direction of the circuit board 10.

[0091] It should be noted that the present invention is not limited to the embodiments and modifications described above, and includes a variety of further modifications. For example, the embodiments described above are described in detail for the purpose of clearly illustrating the present invention, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations.

[0092] 1-9...Electronic device 1a, 1b, 2b...Unit 10, 10'...Circuit board 10h...Through hole (circuit board) 11...Electronic component 12...Connector 20...Housing 20b...Common housing 20h...Through hole (housing) 21, 21'...Storage chamber 21s...Gas phase space 22...Cooling water channel 22'...Deformed channel 22b...Common channel 22b'...Deformed common channel 23...Connecting pipe 24...Supply pipe 25...Discharge pipe 30...Sealing member 101...Base material 102a...Peripheral wiring pattern 301...Unit connecting pipe G1...Boiling refrigerant L1...Liquid refrigerant L1'...Condensed refrigerant L2...Cooling water

Claims

1. An electronic device comprising: a circuit board on which electronic components are mounted; a housing fixed on the main surface of the circuit board so as to cover the mounting positions of the electronic components and forming a storage chamber for storing liquid refrigerant between itself and the circuit board; and a cooling water channel that, together with the storage chamber, constitutes the housing and carries cooling water for cooling boiling refrigerant, which is boiled by the heat generated by the electronic components immersed in the liquid refrigerant in the storage chamber.

2. The electronic device according to claim 1, wherein the circuit board is sandwiched between two housings having the storage chamber and the cooling water channel.

3. The electronic device according to claim 2, wherein the circuit board has through holes.

4. The electronic device according to claim 2, further comprising a connecting pipe for connecting the cooling water channels in the two housings.

5. The electronic device according to claim 4, wherein a cooling water supply pipe is connected to one of the cooling water passages in the two housings, and a cooling water discharge pipe is connected to the other, and the connecting pipe is connected to the cooling water passage at the end opposite to the supply pipe and the discharge pipe.

6. The electronic device according to claim 5, wherein the circuit board has a planar shape with a cutout for the arrangement of the connecting pipe.

7. The electronic device according to claim 1, wherein the cooling water channel is positioned above the storage chamber so as to cover the upper part of the storage chamber in a predetermined state in which the main surface of the circuit board is vertical, and the distance between the wall portion facing the storage chamber and the main surface of the circuit board is gradually widened toward the storage chamber.

8. The electronic device according to claim 7, wherein the extension length extending downward toward the storage chamber is greater than the protruding step that protrudes toward the circuit board in the wall portion.

9. The electronic device according to claim 1, comprising a housing having the storage chamber and the cooling water channel, a plurality of units each comprising a circuit board, and a unit connecting pipe that connects the cooling water channels in adjacent units among the plurality of units stacked in a direction perpendicular to the main surface of the circuit board.

10. The electronic device according to claim 9, wherein each unit is configured in which the circuit board is sandwiched between two housings, and adjacent housings between adjacent units are integrated by having a common water channel that shares the cooling water channel.

11. The electronic device according to claim 10, wherein the housing, among the housings, has the common water channel and is integrated, has through holes.

12. The electronic device according to claim 1, wherein a sealing member for fixing the circuit board to the housing is inserted between the circuit board and the periphery of the housing, and the space between the circuit board and the storage chamber of the housing is sealed by the sealing member.

13. The electronic device according to claim 12, wherein a wiring pattern is continuously arranged on the main surface of the circuit board at a position corresponding to the periphery of the storage chamber, as a base for the sealing member.

14. The electronic device according to claim 1, wherein the circuit board is mounted on a portion extending to the outside of the housing for connecting to an external device, and the storage chamber of the housing has a planar shape that surrounds the connector mounted on the circuit board.

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