JP2018194197A - Heat pipe and electronic equipment - Google Patents

Abstract

To efficiently perform heat transport by enhancing directing of circulation of a refrigerant in a heat pipe.SOLUTION: A heat pipe comprises: an evaporation part installed at a high-temperature part; a condensation part installed at a heat dissipation part; a steam pipe connecting the evaporation part and condensation part to each other and allowing a refrigerant evaporated at the evaporation part to flow toward the condensation part; a liquid pipe connecting the condensation part and the evaporation part to each other and allowing a refrigerant condensed at the condensation part to flow toward the evaporation part; and a first connection part interposed between the liquid pipe and the evaporation part. The first connection part comprises: a plurality of branch flow passages into which the refrigerant flows in from the liquid pipe and which expand a flow area of the refrigerant toward the evaporation part; and a first straightening part which restricts directions in which the refrigerant flows in the branch flow passages to a direction matching a direction from the evaporation part to the condensation part through the steam pipe.SELECTED DRAWING: Figure 1

Description

  The invention disclosed in this specification relates to a heat pipe and an electronic apparatus.

  Since an electronic device generates heat with its operation, various cooling devices have been proposed to cool the electronic device. For example, a CPU (Central Processing Unit) water cooling apparatus having a piston driven by a motor is known (see Patent Document 1). There is also known an electronic device cooling system that includes a bellows that vibrates in response to a volume change caused by vaporization and expansion of a refrigerant, and that includes a power generation / actuator that converts vibration energy generated in the bellows into electrical energy (Patent Document). 2).

  By the way, recent electronic devices have been miniaturized and highly integrated, and accordingly, devices for cooling electronic devices are also required to be small and thin. However, cited document 1 must have a piston driven by a motor, and cited document 2 must have a bellows. For this reason, there are certain limitations on the size and thickness of the cooling device.

  On the other hand, recently, a heat pipe is known as an apparatus that can efficiently transport heat by using a phase change of a refrigerant. Heat pipes can be classified into several types. For example, a type called a loop heat pipe and a type called a self-excited vibration heat pipe are known.

  A conventional loop heat pipe includes an evaporator that receives heat from an object to be cooled and evaporates the refrigerant. The evaporator has a built-in wick. The conventional loop heat pipe further includes a steam pipe for transporting the steam generated in the evaporator, a condenser for condensing the liquefied refrigerant and liquefying it to release heat to the outside, and a liquid for returning the liquefied refrigerant to the evaporator. With tubes. Such a loop heat pipe has a high efficiency of phase change because the refrigerant is thinned at the interface between the wick and the heat transfer surface, and it is common to separate the passage of steam and liquid using the wick. Long-distance heat transport is possible compared to other wick-type heat pipes. However, on the other hand, since the loop heat pipe has a built-in wick, it is difficult to reduce its thickness.

  In self-excited vibration heat pipes, a refrigerant with about half the internal volume is sealed in a plurality of small-diameter channels that meander and reciprocate between the heating part and the cooling part. Cause the flow of heat, thereby transporting heat. The self-excited vibration heat pipe has no built-in parts such as a wick, and has an advantage that the structure is simple and the thickness can be easily reduced. In addition, the self-excited vibration heat pipe can be formed only by the groove-shaped flow path pattern, and is easy to have a thin structure. However, the self-excited vibration heat pipe, on the other hand, uses the vibration of the refrigerant generated in the meandering channel as the driving force for heat transport. There is a problem that decreases.

  In order to efficiently transport heat in a loop heat pipe, it is required to efficiently circulate the refrigerant in a certain direction. As a proposal paying attention to this point, Patent Document 3 is known. In Patent Document 3, a heat pipe that connects a heat receiving portion and a heat radiating portion is provided with a length in a clockwise direction and a length in a counterclockwise direction. In Patent Document 3, a narrow portion having a cross-sectional area smaller than the cross-sectional area of a pipe of a heat pipe connected in an annular shape is provided in a part of the heat pipe.

JP 2006-46304 A JP 2008-235565 A JP-A-6-88685

  If it is patent document 3, it is thought that a heat pipe can be thinned and heat transport can be performed efficiently by making the circulation of a refrigerant into a fixed direction. However, in a situation where further thinning is promoted, a proposal for further increasing the direction of circulation of the refrigerant is demanded.

  In one aspect, it is an object of the heat pipe and the electronic device disclosed in the present specification to enhance the direction of refrigerant circulation in the heat pipe and efficiently perform heat transport.

  The heat pipe disclosed in the present specification connects the evaporation unit installed in the high-temperature unit, the condensation unit installed in the heat dissipation unit, the evaporation unit and the condensation unit, and the refrigerant evaporated in the evaporation unit is A steam pipe that flows toward the condensing part, a condenser that connects the condensing part and the evaporation part, a liquid pipe that flows the refrigerant condensed in the condensing part toward the evaporation part, and the liquid pipe and the evaporation part A first connecting portion interposed therebetween, wherein the first connecting portion receives the refrigerant from the liquid pipe and expands the flow area of the refrigerant toward the evaporation portion. And a first rectification unit that regulates a direction in which the refrigerant flows in the branch flow path in a direction that coincides with a direction from the evaporation unit toward the condensing unit through the vapor pipe.

  An electronic device disclosed in the present specification is an electronic device including a substrate on which a high-temperature part and a heat dissipation part are set, and a heat pipe installed on the substrate, wherein the heat pipe is installed on the high-temperature part. An evaporating unit, a condensing unit installed in the heat dissipating unit, a vapor pipe connecting the evaporating unit and the condensing unit, and flowing a refrigerant evaporated in the evaporating unit toward the condensing unit, and the condensing A liquid pipe that connects the liquid section and the evaporation section, and causes the refrigerant condensed in the condensation section to flow toward the evaporation section, and a first connection section that is interposed between the liquid pipe and the evaporation section. The first connection portion includes a plurality of branch flow channels that flow in from the liquid pipe and expands a flow area of the refrigerant toward the evaporation portion, and the refrigerant flows in the branch flow channels. Direction from the evaporating part to the condensing part through the steam pipe And it includes a first rectifier unit for restricting the matching direction.

  According to the heat pipe and the electronic device disclosed in the present specification, the direction of the circulation of the refrigerant in the heat pipe can be strengthened, and the heat transport can be efficiently performed.

FIG. 1 is an explanatory diagram illustrating a schematic configuration of an electronic apparatus including the heat pipe according to the first embodiment. FIG. 2 is an explanatory view showing the structure of the first connection portion provided in the heat pipe of the first embodiment. FIG. 3A is an explanatory view schematically showing a state where the liquid phase refrigerant is supplied to the evaporation section of the first embodiment and the flow area is expanded, and FIG. It is explanatory drawing which shows a mode that the refrigerant | coolant of a phase is supplied typically. FIG. 4A is an explanatory diagram showing a state in which the refrigerant easily flows in the rectifying unit, and FIG. 4B is an explanatory diagram showing a state in which the refrigerant hardly flows in the rectifying unit. FIG. 5 is an explanatory diagram showing the structure of the second connection portion provided in the first embodiment. FIG. 6 is an explanatory view schematically showing a heat pipe test model for confirming the rectifying effect. FIG. 7 is a graph showing the relationship between the input heat quantity and the pressure loss in the test model. FIG. 8 is an explanatory view showing the structure of the first connecting portion in the second embodiment. FIG. 9 is a graph showing the relationship between the channel diameter and the pressure. FIG. 10A is an explanatory diagram showing a structure of a first connection part provided in the third embodiment, and FIG. 10B is an explanatory diagram showing a structure of a second connection part provided in the third embodiment. is there.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, in the drawings, the dimensions, ratios, and the like of each part may not be shown so as to completely match the actual ones. Further, depending on the drawings, components that are actually present may be omitted for convenience of explanation, or dimensions may be exaggerated from the actual drawing.

(First embodiment)
First, with reference to FIG. 1 thru | or FIG. 6, the heat pipe 10 of 1st Embodiment and the electronic device 100 which mounts this are demonstrated. FIG. 1 is an explanatory diagram illustrating a schematic configuration of an electronic apparatus including the heat pipe according to the first embodiment. FIG. 2 is an explanatory view showing the structure of the first connection portion provided in the heat pipe of the first embodiment. FIG. 3A is an explanatory view schematically showing a state where the liquid phase refrigerant is supplied to the evaporation section of the first embodiment and the flow area is expanded, and FIG. It is explanatory drawing which shows a mode that the refrigerant | coolant of a phase is supplied typically. FIG. 4A is an explanatory diagram showing a state in which the refrigerant easily flows in the rectifying unit, and FIG. 4B is an explanatory diagram showing a state in which the refrigerant hardly flows in the rectifying unit. FIG. 5 is an explanatory diagram showing the structure of the second connection portion provided in the first embodiment. FIG. 6 is an explanatory view schematically showing a heat pipe test model for confirming the rectifying effect. FIG. 7 is a graph showing the relationship between the input heat quantity and the pressure loss in the test model.

  Referring to FIG. 1, a heat pipe 10 is mounted on the electronic device 100. The electronic device 100 in the present embodiment is a main part of a notebook PC (Personal Computer). However, this is an example, and other electronic devices may be used. The electronic device 100 includes a housing 101, and a substrate 102 is incorporated therein. On the substrate 102, a CPU (Central Processing Unit) and other electronic elements are mounted. Some electronic elements generate heat during use. In the present embodiment, the periphery of such a heating element is set as the high temperature portion 103. In this embodiment, the heat radiating part 104 is set at a position away from the high temperature part 103. The heat radiating unit 104 can be appropriately set according to the layout in the housing 101. The heat dissipation unit 104 may include a heat sink or the like.

  The heat pipe 10 includes an evaporator 11 and a condenser 12. In addition, the heat pipe 10 includes a vapor pipe 13 that connects the evaporation unit 11 and the condensation unit 12 and flows the refrigerant 20 evaporated in the evaporation unit 11 toward the condensation unit 12. In the present embodiment, four steam pipes 13 are provided, but the number of steam pipes 13 is not limited to this. The heat pipe 10 includes a liquid pipe 14 that connects the condensing unit 12 and the evaporating unit 11 and flows the refrigerant 20 condensed in the condensing unit 12 toward the evaporating unit 11. The refrigerant 20 enclosed in the heat pipe 10 can change phase between the liquid-phase refrigerant 20a and the gas-phase refrigerant 20b in the heat pipe 10. Although the liquid phase refrigerant 20a may be mixed in the vapor pipe 13, the gas phase refrigerant 20b mainly flows. In the liquid pipe 14, the liquid phase refrigerant 20a mainly flows. In this embodiment, the refrigerant 20 containing n-pentane is used, but conventionally known refrigerants such as water and ethanol can be used.

  The evaporation unit 11 is provided with a plurality of fins 11a. The fin 11a increases the contact area with the liquid-phase refrigerant 20a and improves the evaporation efficiency. The condensing unit 12 is also provided with a plurality of fins 12a. The fins 12a increase the contact area with the gas-phase refrigerant 20b and improve the condensation efficiency.

  The heat pipe 10 includes a first connection part 15 interposed between the liquid pipe 14 and the evaporation part 11. Referring to FIG. 2, the first connecting portion 15 includes a plurality of branch flow paths 151 to 155 that flow in the refrigerant 20 from the liquid pipe 14 and expand the flow area of the refrigerant 20 toward the vapor pipe 13. The first connection portion 15 is connected to the liquid pipe 14 at one opening portion, but is branched into a plurality of branch flow paths 151 to 155 inside. As a result, as shown in FIG. 3A, the flow area of the liquid-phase refrigerant 20a flowing from the liquid pipe 14 can be expanded in the width direction shown in FIG. By enlarging the flow area of the liquid refrigerant 20a, the liquid refrigerant 20a can be thinned. The liquid phase refrigerant 20a can be actively evaporated by being thinned. When the liquid-phase refrigerant 20a evaporates actively, the cooling efficiency is improved. In order to promote the evaporation of the liquid-phase refrigerant 20a, it is effective to increase the area in contact with the high temperature portion 103 set on the substrate 102. Therefore, in this embodiment, the branch flow paths 151 to 155 are arranged in a fan shape so that the liquid-phase refrigerant 20a spreads in a plane parallel to the mounting surface of the substrate 102, and is shown in FIG. 1 and FIG. The liquid refrigerant 20a spreads in the width direction.

  Here, a comparative example will be described with reference to FIG. The evaporation unit 5 of the comparative example includes the fins 5a as in the present embodiment and promotes the evaporation of the liquid-phase refrigerant 20a, but includes only a single opening 51 near the center. For this reason, the liquid-phase refrigerant 20a that has flowed into the evaporation section 5 from the opening 51 has a high bulk in the vicinity of the opening 51 and has a thick film shape. If the liquid refrigerant 20a is thick, it is difficult to evaporate and the cooling efficiency is reduced. In addition, referring to FIG. 3B, the liquid-phase refrigerant 20a does not reach the end portions 5b on both sides of the evaporation unit 5, and is depleted, so-called dryout regions are formed. As a result, the cooling efficiency in the evaporation part 5 falls.

  According to this embodiment, since the liquid phase refrigerant 20a spreads in a thin film shape over a wide range, the cooling efficiency is high. When the liquid-phase refrigerant 20a actively undergoes a phase change and steam is generated, the momentum of circulation of the refrigerant 20 is increased and the heat transport efficiency is improved.

  Each of the plurality of branch flow paths 151 to 155 formed in the first connection unit 15 includes a Tesla valve 17 as a first rectification unit. The first rectification unit can employ a fluid diode, and in this embodiment, a Tesla valve 17 is employed. The Tesla valve 17 regulates the direction in which the refrigerant 20 flows in each of the branch flow paths 151 to 155 in a direction that coincides with the direction from the evaporation unit 11 to the condensation unit 12 through the vapor pipe 13.

  Here, the rectification effect by the Tesla valve 17 will be described with reference to FIGS. 4 (A) and 4 (B). The Tesla valve 17 includes a bypass channel 172 that connects a first branch point 171a and a second branch point 171b provided in the main channel 171. When the fluid flows into the main channel 171 from the left in FIG. 4A as indicated by an arrow 18 in FIG. 4A, the fluid (refrigerant 20) is bypassed at the first branch point 171a. In order to flow into the flow direction, the flow direction is greatly bent. This is because, at the first branch point 171a, the angle formed between the main flow path 171 and the bypass flow path 172 after passing through the first branch point 171a is an obtuse angle, and the path turns back. . For this reason, the fluid flowing through the main channel 171 is unlikely to flow into the bypass channel 172. Even if the fluid flows into the bypass channel 172, the fluid that has passed through the bypass channel 172 smoothly merges with the flow of the main channel 171 at the second branch point 171b. It will not be a resistance.

  On the other hand, when a fluid flows into the main channel 171 from the right side in FIG. 4B as indicated by an arrow 19a shown in FIG. 4B, the fluid (refrigerant 20) is bypassed at the second branch point 171b. It flows into the road 172. This is because the angle formed by the main flow path 171 and the bypass flow path 172 after passing through the second branch point 171b is an acute angle at the second branch point 171b. The fluid flowing into the bypass channel 172 changes the direction of the flow in the bypass channel 172 as indicated by an arrow 19b and joins the main channel 171 at the first branch point 171a. Collide with the flow of For this reason, the resistance of the flow of the main flow path 171 increases.

  In the heat pipe 10, the liquid-phase refrigerant 20 a changes into a gas-phase refrigerant 20 b in a region centering on the evaporation unit 11. With such a phase change, the refrigerant 20 expands, whereby the refrigerant 20 tries to move in the heat pipe 10. Here, since the fluid tends to flow in a direction in which it easily flows, it tends to flow as indicated by an arrow 18 shown in FIG. Since the Tesla valve 17 is provided in the branch flow paths 151 to 155, the flow direction of the refrigerant 20 in each branch flow path 151 to 155 coincides with the direction from the evaporation unit 11 to the condensation unit 12 through the vapor pipe 13. Regulated in direction. Thus, in this embodiment, the orientation of the circulation of the refrigerant 20 in the heat pipe 10 is strengthened.

  In addition, in the present embodiment, since the plurality of Tesla valves 17 are arranged in multiple stages in series along the flow direction in each of the branch flow paths 151 to 155, the direction of circulation of the refrigerant 20 in the heat pipe 10 is determined. Has been strengthened.

  The heat pipe 10 further includes a second connection part 16 interposed between the condensing part 12 and the liquid pipe 14. Referring to FIG. 5, the second connection unit 16 includes a plurality of merge channels 161 to 165 that allow the refrigerant 20 to flow from the condensing unit 12 and collect the refrigerant 20 toward the liquid pipe 14. The second connection portion 16 is connected to the liquid pipe 14 at one opening portion, and includes a plurality of merging flow paths 161 to 165 therein. Referring to FIG. 1, the condensing part 12 extends in the width direction, and the side connected to the condensing part 12 of the second connecting part 16 is formed wide like the condensing part 12. The second connecting portion 16 is provided with the joining flow paths 161 to 165 so as to form a single flow path from the end portion thus formed wide toward the liquid pipe 14. Thus, the contact area of the gaseous-phase refrigerant | coolant 20b increases by providing the some confluence | merging flow paths 161-165. When the contact area of the gas-phase refrigerant 20b increases, the heat transfer from the gas-phase refrigerant 20b to the heat radiation unit 104 is promoted, and the phase change from the gas-phase refrigerant 20b to the liquid-phase refrigerant 20a is facilitated. Thereby, the cooling efficiency of the heat pipe 10 is improved.

  In order to promote the condensation of the gas-phase refrigerant 20b, it is effective to increase the area in contact with the heat radiation unit 104 set on the substrate 102. Therefore, in this embodiment, the merging channels 161 to 165 are arranged in a fan shape so that the gas-phase refrigerant 20b spreads in a plane parallel to the mounting surface of the substrate 102.

  Each of the plurality of merging flow paths 161 to 165 formed in the second connection part 16 includes a Tesla valve 17 as a second rectification part. The second rectification unit can adopt the same structure as the first rectification unit. The Tesla valve 17 equipped in the second connection part 16 regulates the direction in which the refrigerant 20 flows in each of the merged flow paths 161 to 165 to a direction that coincides with the direction from the evaporation part 11 to the condensation part 12 through the steam pipe 13. To do. That is, the Tesla valve 17 as the second connection portion causes the refrigerant 20 to flow in the same direction as the Tesla valve 17 as the first rectification portion. That is, the Tesla valve 17 as the second connection portion causes the refrigerant 20 to flow in the direction from the condensing unit 12 toward the liquid pipe 14.

  In the present embodiment, the second connection portion 16 is provided, but the second connection portion 16 may be omitted. In this case, the flow direction of the refrigerant 20 is performed by the Tesla valve 17 provided in the first connection portion 15. Alternatively, the first connection portion 15 may be eliminated and only the second connection portion 16 may be provided. Also in this case, since the second connecting portion 16 is equipped with the Tesla valve 17, the flow direction of the refrigerant 20 can be directed.

  In such a heat pipe 10, the evaporation section 11, the condensation section 12, the steam pipe 13, the liquid pipe 14, the first connection section 15, and the second connection section 16 are formed on a single copper thin plate by half etching. The other copper thin plates are laminated and diffusion bonded. Thereby, the heat pipe 10 can be thinned. According to the half-etching process, a complicated path can be easily formed, and the flow path of the Tesla valve 17 can also be formed. In the present embodiment, a copper thin plate is used, but other materials may be used.

  In the present embodiment, the liquid tube 14 is also formed of a copper thin plate in the same manner. However, for example, another tube-like member may be attached to form the liquid tube 14.

  In such a heat pipe 10, the evaporation unit 11 is aligned with the position of the high temperature unit 103 set on the substrate 102, and the condensing unit 12 is aligned with the position of the heat dissipation unit 104 set on the substrate 102. It is installed.

  Here, with reference to FIG.6 and FIG.7, the rectification effect by the structure with which the heat pipe 10 is provided is demonstrated in detail. FIG. 6 is an explanatory view schematically showing a heat pipe test model for confirming the rectifying effect. FIG. 7 is a graph showing the relationship between the input heat quantity and the pressure loss in the test model.

  A test model 50 shown in FIG. 6 includes main elements of the heat pipe 10 of the embodiment. In the test model 50, elements common to the heat pipe 10 will be described with the same reference numerals.

  In order to verify the effect of the direction of circulation of the refrigerant 20 in the present embodiment, a test model 50 as shown in FIG. 6 was prepared. The test model 50 includes an evaporation unit 11 and a condensation unit 12. In addition, the test model 50 includes a vapor pipe 13 that connects the evaporation unit 11 and the condensation unit 12 and causes the refrigerant 20 evaporated in the evaporation unit 11 to flow toward the condensation unit 12. Further, the test model 50 includes a liquid pipe 14 that connects the condensing unit 12 and the evaporating unit 11 and flows the refrigerant 20 condensed in the condensing unit 12 toward the evaporating unit 11. Furthermore, the test model 50 includes a first connection portion 15 interposed between the liquid tube 14 and the evaporation portion 11. The first connecting part 15 is equipped with a Tesla valve 17 as a rectifying part. Using such a test model 50, the pressure loss in the forward direction indicated by arrow 21 and the reverse direction indicated by arrow 22 in FIG. 6 was compared. The forward direction is the direction of flow from the evaporator 11 to the condenser 12 through the vapor pipe 13 and back to the evaporator 11 again through the liquid pipe 14 and the Tesla valve 17. The reverse direction is the direction of flow from the evaporator 11 to the condenser 12 through the Tesla valve 17 and the liquid pipe 14 and back to the evaporator 11 again through the steam pipe 13.

  Note that the test model 50 is not equipped with the second connection portion 16. This is because the first connecting portion 15 includes the Tesla valve 17 and includes the basic components, which is sufficient for verifying the effect of directing the circulation of the refrigerant 20.

  The Tesla valve 17 is a flow passage having a rectangular cross section with a width of 1 mm and a depth of 1 mm. Three branch flow paths 151 to 153 are arranged in parallel in the first connection portion 15. Each of the branch flow paths 151 to 153 is provided with five Tesla valves 17 along the flow direction.

  The steam pipe 13 is formed by arranging five flow paths having a width of 10 mm and a depth of 1 mm in parallel. The liquid pipe 14 has one flow path having a width of 20 mm and a depth of 1 mm. As the refrigerant, n-pentane was assumed, and the heat input condition was 30 to 100 W.

  It is assumed that the refrigerant 20 evaporates in the evaporation unit 11 and the temperature at that time is 60 ° C. Moreover, the refrigerant | coolant 20 condenses in the condensation part 12, and the temperature at that time is assumed to be 25 degreeC. And the vapor | steam which is the gaseous-phase refrigerant | coolant 20b distribute | circulates to the vapor pipe 13, and the forward direction shown by the arrow 21 assumes that the liquid-phase refrigerant | coolant 20a distribute | circulates to the liquid pipe 14 and the 1st connection part 15. The pressure loss in the reverse direction indicated by arrow 22 was calculated.

  As the amount of heat input increases, the amount of refrigerant evaporated increases and the flow rate increases. Referring to FIG. 7, it can be seen that the pressure loss in each direction increases as the amount of heat increases, but the reverse direction increases rapidly while the forward direction increases slowly. Such a pressure difference between the forward direction and the reverse direction creates a rectifying effect that causes the refrigerant 20 to flow in the forward direction. In the forward direction and the reverse direction, the configuration of the path is the same and the direction of passing through the Tesla valve 17 is different, so that it can be confirmed that this creates a pressure difference that produces a rectifying effect. As described above, it was confirmed that the direction of circulation of the refrigerant 20 is directed by providing the Tesla valve 17.

  Thus, the heat pipe 10 can strengthen the direction of the circulation of the refrigerant and efficiently perform the heat transport. In the present embodiment, since the structure such as the wick is not included, the heat pipe 10 can be thinned.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIGS. FIG. 8 is an explanatory view showing the structure of the first connecting portion in the second embodiment. FIG. 9 is a graph showing the relationship between the channel diameter and the pressure.

  In 2nd Embodiment, it replaces with the 1st connection part 15 in 1st Embodiment, and is provided with the 1st connection part 25. FIG. Referring to FIG. 8, the first connection unit 25 includes branch channels 251 a, 252 a, and 253 a whose channel diameter is gradually reduced from the liquid pipe 14 toward the evaporation unit 11. Specifically, the first connection unit 25 includes a first level 251, a second level 252, and a third level 253 in order from the liquid pipe 14 toward the evaporation unit 11.

  The first hierarchy 251 includes four branch channels 251a. Each branch channel 251a is provided with a Tesla valve 251a1. The channel diameter of each branch channel 251a is d1. The structure of the Tesla valve 251a1 is common to the Tesla valve 17 in the first embodiment.

  The second hierarchy 252 includes a total of eight branch channels 252a branched into two branches from each branch channel 252a. Each branch passage 252a is provided with a Tesla valve 252a1. The channel diameter of each branch channel 252a is d2. The structure of the Tesla valve 252a1 is common to the Tesla valve 17 in the first embodiment.

  The third hierarchy 253 includes a total of 16 branch channels 253a branched into two branches from each branch channel 252a. Each branch passage 253a is provided with a Tesla valve 253a1. The channel diameter of each branch channel 253a is d3. The structure of the Tesla valve 253a1 is common to the Tesla valve 17 in the first embodiment.

  Here, the relationship between the flow path diameters is d1> d2> d3. In this way, the first connection portion 25 includes a branch flow path whose flow path diameter is gradually reduced from the liquid pipe 14 toward the evaporation section 11. On the other hand, the flow path diameter of the evaporation unit 11 where the branch flow path 253a belonging to the third hierarchy 253 opens is de, and the flow path diameter de is larger than d1 to d3.

  The first connecting portion 25 is provided with the branching channels 251 a, 252 a, and 253 a whose channel diameter is gradually reduced from the liquid pipe 14 toward the evaporation unit 11, between the evaporation unit 11 and the first connection unit 25. This is because the capillary force is used. Here, the relationship between the flow path diameter and the pressure will be described with reference to FIG. Referring to FIG. 9, it can be seen that the smaller the channel diameter, the larger the pressure, and the larger the channel diameter, the smaller the pressure. When the refrigerant 20 flows into regions having different flow path diameters, the pressure difference acts as a capillary force. That is, the greater the pressure difference, the higher the backflow prevention effect.

  In the present embodiment, since the flow path diameter of the evaporation unit 11 is de, the larger the difference between the diameter of the branch flow path that flows into the evaporation unit 11 and the flow path diameter de, the greater the capillary force, and the liquid phase refrigerant 20a. Becomes easy to permeate into the evaporation unit 11 side. Such a capillary force increases the direction of circulation of the refrigerant 20.

  In the present embodiment, the difference between the pressure at the flow path diameter d3 and the pressure at the flow path diameter de of the evaporation section 11 becomes a pressure difference for preventing backflow, and an action of flowing the refrigerant 20 in a certain direction can be obtained. .

  The reason why the flow path diameter is gradually reduced is that the flow path diameter is gradually reduced to reach a desired flow path diameter while suppressing pressure loss.

(Third embodiment)
Next, a third embodiment will be described with reference to FIGS. 10 (A) and 10 (B). FIG. 10A is an explanatory diagram showing a structure of a first connection part provided in the third embodiment, and FIG. 10B is an explanatory diagram showing a structure of a second connection part provided in the third embodiment. is there.

  The third embodiment includes the first connection portion 25 as in the second embodiment, and includes the second connection portion 26 instead of the second connection portion 16 in the first embodiment.

  Referring to FIG. 10B, the second connection unit 26 includes a first level 261 and a second level 262 in order from the condensing unit 12 toward the liquid pipe 14.

  The first hierarchy 261 includes four merging channels 261a. Each merging channel 261a is provided with a Tesla valve 261a1. The flow path diameter of each merging flow path 261a is d1. The structure of the Tesla valve 261a1 is common to the Tesla valve 17 in the first embodiment.

  The second level 262 includes two merging channels 262a in which two merging channels 261a merge. Each merging channel 262a is provided with a Tesla valve 262a1. The flow path diameter of each merging flow path 262a is d1. The structure of the Tesla valve 261a1 is common to the Tesla valve 17 in the first embodiment. The two merge flow paths 262a finally merge into one.

  As described above, the flow path diameter of the merge flow path 261a included in the second connection portion 26 is d1, while the flow path diameter of the branch flow path 253a included in the first connection portion 25 is d3. Here, there is a relationship of d1> d3.

  Thus, in this embodiment, the diameter of the opening located in the condensing part 12 of a confluence | merging flow path is set larger than the diameter of the opening located in the evaporation part 11 of a branch flow path. Thereby, the orientation of the circulation of the refrigerant 20 can be strengthened on both sides of the capillary force and the pressure loss difference between the first connection portion 25 and the second connection portion 26.

  Although the preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the specific embodiment, and various modifications, within the scope of the gist of the present invention described in the claims, It can be changed.

DESCRIPTION OF SYMBOLS 10 Heat pipe 5, 11 Evaporating part 5a, 11a Fin 12 Condensing part 12a Fin 13 Steam pipe 14 Liquid pipe 15 1st connection part 16 2nd connection part 17 Tesla valve (rectification | straightening part)
20a Liquid-phase refrigerant 20b Gas-phase refrigerant 25 First connection portion 251 First layer 252 Second layer 253 Third layer 100 Electronic device 101 Housing 102 Substrate 103 High-temperature unit 104 Heat radiation unit

Claims (7)

An evaporation section installed in the high temperature section;
A condensing part installed in the heat radiating part;
A steam pipe that connects the evaporation unit and the condensing unit, and causes the refrigerant evaporated in the evaporation unit to flow toward the condensing unit;
A liquid pipe that connects the condensing unit and the evaporating unit, and causes the refrigerant condensed in the condensing unit to flow toward the evaporating unit;
A first connection part interposed between the liquid pipe and the evaporation part,
The first connection portion includes a plurality of branch flow channels that flow in the refrigerant from the liquid pipe and expand the flow area of the refrigerant toward the evaporation portion, and a direction in which the refrigerant flows in the branch flow channels. And a first rectifying unit that regulates in a direction that coincides with a direction from the evaporation unit toward the condensing unit through the vapor pipe. A second connecting part interposed between the condensing part and the liquid pipe;
The second connection portion includes a plurality of merging passages in which the refrigerant flows from the condensing portion and collects the refrigerant toward the liquid pipe, and a direction in which the refrigerant flows in the merging passage, The heat pipe according to claim 1, wherein the heat pipe is regulated in a direction that coincides with a direction from the evaporation unit toward the condensing unit through a steam pipe.   The heat pipe according to claim 1 or 2, wherein the first rectification unit is provided in multiple stages along the branch flow path.   The heat pipe according to any one of claims 1 to 3, wherein the branch channel has a channel diameter gradually reduced from the liquid pipe toward the evaporation unit.   3. The heat pipe according to claim 2, wherein a diameter of an opening located in the condensing part of the confluence channel is larger than a diameter of an opening located in the evaporation part of the branch flow path. An evaporation section installed in the high temperature section;
A condensing part installed in the heat radiating part;
A steam pipe that connects the evaporation unit and the condensing unit, and causes the refrigerant evaporated in the evaporation unit to flow toward the condensing unit;
A liquid pipe that connects the condensing unit and the evaporating unit, and causes the refrigerant condensed in the condensing unit to flow toward the evaporating unit;
A second connecting part interposed between the condensing part and the liquid pipe,
The second connection portion includes a plurality of merging passages in which the refrigerant flows from the condensing portion and collects the refrigerant toward the liquid pipe, and a direction in which the refrigerant flows in the merging passage, A heat pipe comprising: a second rectification unit that regulates in a direction that coincides with a direction from the evaporation unit toward the condensing unit through a steam pipe. An electronic device comprising a substrate on which a high temperature part and a heat dissipation part are set, and a heat pipe installed on the substrate,
The heat pipe is
An evaporation section installed in the high temperature section;
A condensing part installed in the heat dissipating part;
A steam pipe that connects the evaporation unit and the condensing unit, and causes the refrigerant evaporated in the evaporation unit to flow toward the condensing unit;
A liquid pipe that connects the condensing unit and the evaporating unit, and causes the refrigerant condensed in the condensing unit to flow toward the evaporating unit;
A first connection part interposed between the liquid pipe and the evaporation part,
The first connection portion includes a plurality of branch flow channels that flow in the refrigerant from the liquid pipe and expand the flow area of the refrigerant toward the evaporation portion, and a direction in which the refrigerant flows in the branch flow channels. A first rectifying unit that regulates in a direction that coincides with a direction from the evaporation unit toward the condensing unit through the steam pipe;
With electronic equipment.

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