JP2015132400A - Loop type heat pipe, manufacturing method of the same, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce heat resistance between a loop type heat pipe and a heating component in the loop type heat pipe, a manufacturing method of the loop type heat pipe, and an electronic device.SOLUTION: A loop type heat pipe includes: an evaporator 33 which thermally contacts with a first heating component 13 and evaporates a working fluid C by heat of the first heating component 13; a condenser 34 which liquefies the working fluid C; a liquid pipe 36 which connects the evaporator 33 with the condenser 34; and a steam pipe 35 which connects the evaporator 33 with the condenser 34 and forms a loop with the liquid pipe 36. The evaporator 33 is formed by laminating multiple metal layers 38, 39. At least one layer of the multiple metal layers 38, 39 is folded to form a cover 37 that covers the first heating component 13.

Description

  The present invention relates to a loop heat pipe, a manufacturing method thereof, and an electronic apparatus.

  With the advent of an advanced information society, mobile electronic devices such as smartphones and tablet terminals are spreading. Since mobile electronic devices are thinned so that they can be easily carried, it is difficult to provide a blower fan for cooling heat-generating components such as a CPU (Central Processing Unit).

  As a method for cooling the heat generating component, for example, there is a method of transporting the heat of the heat generating component to the outside with a metal plate or a heat diffusion sheet having good thermal conductivity. However, in this method, the heat that can be transported is limited by the thermal conductivity of the metal plate or the thermal diffusion sheet. For example, the thermal conductivity of a graphite sheet used as a thermal diffusion sheet is about 500 W / mK to 1500 W / mK. With this thermal conductivity, the heat generating component is cooled when the heat generation amount of the heat generating component increases. It becomes difficult.

  Therefore, a heat pipe has been studied as a device that actively cools heat-generating components.

  The heat pipe is a device for transporting heat by utilizing the phase change of the working fluid, and has a higher thermal conductivity than that of the heat diffusion sheet. For example, a heat pipe having a diameter of 3 mm shows a large thermal conductivity of about 1500 W / mK to 2500 W / mK.

  There are several types of heat pipes. The loop heat pipe includes an evaporator that vaporizes the working fluid by the heat of the heat generating component, and a condenser that cools and vaporizes the vaporized working fluid. The evaporator and the condenser are connected by a liquid pipe and a vapor pipe that form a loop-shaped flow path, and the working fluid flows through the path in one direction.

  In this way, the direction of flow of the working fluid in the loop type heat pipe is one direction. Therefore, the resistance that the working fluid receives less compared to the heat pipe in which the liquid-phase working fluid and its vapor reciprocate in the pipe, and efficiently. Heat transport can be performed.

  The loop heat pipe has room for improvement in terms of reducing the thermal resistance between the heat generating components.

JP-A-8-288868 JP 2010-19495 A

  An object of the present invention is to reduce a thermal resistance between a loop heat pipe and a heat generating component in the loop heat pipe, a manufacturing method thereof, and an electronic device.

  According to one aspect of the disclosure below, an evaporator that is in thermal contact with the first heat generating component and vaporizes the working fluid by the heat of the first heat generating component, and a condenser that liquefies the working fluid A liquid pipe that connects the evaporator and the condenser; a vapor pipe that connects the evaporator and the condenser and forms a loop with the liquid pipe; and the evaporator has a plurality of Provided is a loop heat pipe in which a metal layer is laminated and at least one of the plurality of metal layers is bent to cover the first heat-generating component.

  Further, according to another aspect of the disclosure, the heat generating component and a loop heat pipe that cools the heat generating component, the loop heat pipe is in thermal contact with the heat generating component, and An evaporator that vaporizes a working fluid by heat of the heat generating component, a condenser that liquefies the working fluid, a liquid pipe that connects the evaporator and the condenser, and the evaporator and the condenser are connected. A vapor pipe that forms a loop with the liquid pipe, and the evaporator is formed by laminating a plurality of metal layers, and a cover that covers at least one of the metal layers and covers the heat generating component An electronic device is provided.

  Furthermore, according to another aspect of the disclosure, a step of forming each of an evaporator, a condenser, a liquid pipe, and a vapor pipe by laminating a plurality of metal layers, and a plurality of the metals in the evaporator A method of manufacturing a loop heat pipe, comprising: a step of forming a cover that covers a heat-generating component that is in thermal contact with the evaporator by bending at least one of the layers; and a step of injecting a working fluid into the liquid pipe. Provided.

  According to the following disclosure, the evaporator of the loop heat pipe is formed by laminating a plurality of metal layers, and at least one of the metal layers is bent to cover the first heat-generating component. To do. According to this, since a heat conductive sheet or the like for thermally connecting the cover and the loop heat pipe is not required, a thermal resistance due to the heat conductive sheet or the like is not generated, and the cover and the loop heat pipe are not generated. It is possible to reduce the thermal resistance between the two.

FIG. 1 is a schematic diagram of a loop heat pipe used for the study. FIG. 2 is a cross-sectional view taken along the line II of FIG. FIG. 3 is an exploded perspective view of an electronic device that houses the loop heat pipe used in the study. 4 is a cross-sectional view of the electronic device of FIG. 3 with the upper housing removed. FIG. 5 is an exploded perspective view of the electronic apparatus according to the first embodiment. FIG. 6 is a perspective view of the electronic device according to the first embodiment during assembly. FIG. 7 is a perspective view of the loop heat pipe according to the first embodiment. 8 is a cross-sectional view taken along the line II-II in FIG. FIGS. 9A and 9B are side views in the middle of manufacturing the loop heat pipe according to the first embodiment. FIG. 10 is a plan view of a laminate obtained by laminating metal layers in the first embodiment when viewed from the uppermost second metal layer. FIG. 11 is a perspective view of a laminate of the first metal layer and the second metal layer obtained in the first embodiment. FIG. 12 is a perspective view (No. 1) in the middle of manufacturing the loop heat pipe according to the first embodiment. FIG. 13: is a perspective view (the 2) in the middle of manufacture of the loop type heat pipe which concerns on 1st Embodiment. FIG. 14 is a perspective view (No. 3) in the middle of manufacturing the loop heat pipe according to the first embodiment. FIG. 15 is a perspective view of the loop heat pipe according to the first embodiment in which the front and back are reversed from those in FIG. 16 is a cross-sectional view taken along line III-III in FIG. FIG. 17: is sectional drawing of the evaporator with which the loop type heat pipe which concerns on 2nd Embodiment is provided, and its vicinity. FIG. 18 is a partial plan view of the second metal layer in the second embodiment. FIGS. 19A and 19B are perspective views schematically showing a method of providing a reinforcing plate in the second embodiment. FIG. 20 is an enlarged cross-sectional view of a metal layer used in the third embodiment. FIG. 21 is a cross-sectional view of the evaporator of the loop heat pipe according to the third embodiment and the vicinity thereof. FIG. 22 is an exploded perspective view of an electronic device according to the fourth embodiment. FIG. 23 is an exploded perspective view of an electronic apparatus according to the fifth embodiment. FIG. 24 is a plan view of a laminate obtained by laminating metal layers in the fifth embodiment when viewed from the uppermost second metal layer. FIG. 25 is a perspective view (No. 1) in the middle of manufacturing the loop heat pipe according to the fifth embodiment. FIG. 26 is a perspective view (part 2) in the middle of manufacturing the loop heat pipe according to the fifth embodiment. FIG. 27 is a perspective view (No. 3) in the middle of manufacturing the loop heat pipe according to the fifth embodiment.

  Prior to the description of the present embodiment, items studied by the inventor will be described.

  FIG. 1 is a schematic diagram of a loop heat pipe used for the study.

  The loop heat pipe 1 is accommodated in a mobile electronic device such as a smartphone, and includes an evaporator 3 and a condenser 4.

  A vapor pipe 5 and a liquid pipe 6 are connected to the evaporator 3 and the condenser 4, and a loop-shaped flow path 7 a through which the working fluid C flows is formed by these pipes 5 and 6.

  FIG. 2 is a cross-sectional view taken along the line II of FIG.

  As shown in FIG. 2, the loop heat pipe 1 is formed by laminating a plurality of copper layers 7. The copper layers 7 are bonded to each other by, for example, diffusion bonding, and a flow path 7a through which the working fluid C flows is defined by the copper layers 7. Such a flow path 7 a is defined not only in the vapor pipe 5 but also in the evaporator 3, the condenser 4, and the liquid pipe 6.

  By forming the loop heat pipe 1 from the copper layer 7 laminated in this way, it becomes easy to reduce the thickness of the loop heat pipe 1 and promote the thinning of electronic devices such as smartphones. Is possible.

  FIG. 3 is an exploded perspective view of the electronic device 2 in which the loop heat pipe 1 is accommodated.

  The electronic device 2 is a smartphone and includes a lower housing 14 and an upper housing 15. Each housing 14 and 15 is made of, for example, resin, and the upper housing 15 is provided with a liquid crystal display unit 15a.

  A circuit board 16 is accommodated in the lower housing 14, and a first heat generating component 13 such as a CPU is fixed on the circuit board 16.

  The heat generating component 13 is covered with a metal cover 12. The cover 12 has a function of electromagnetically shielding the first heat generating component 13 and protecting the first heat generating component 13 from an external mechanical shock, and evaporating the loop heat pipe 1. Secured to vessel 3.

  Further, a sheet metal 11 having substantially the same shape as the liquid crystal display unit 15 a is provided on the loop heat pipe 1. The sheet metal 11 has a function of making the heat generated in the liquid crystal display unit 15a uniform on the back surface by being in close contact with the back surface of the liquid crystal display unit 15a. The sheet metal 11 also has a function of shielding external electromagnetic waves.

  When the first heat generating component 13 generates heat in such an electronic device 2, the working fluid C is vaporized in the evaporator 3 of the loop heat pipe 1, and the first heat generating component 13 can be cooled by the heat of vaporization. .

  FIG. 4 is a cross-sectional view of the electronic device 2 with the upper housing 15 removed.

  In FIG. 4, the same elements as those described in FIGS. 1 and 2 are denoted by the same reference numerals as those in FIGS.

  As shown in FIG. 4, a clad material 19 made of a magnesium alloy or the like and a frame 18 are provided on the lower housing 14 in this order. The frame 18 and the clad material 19 absorb the difference between the shape of the inner surface of the lower housing 14 and the outer shape of the battery 17 and play a role of stably holding the battery 17 and the circuit board 16 in the lower housing 14. .

  The above-described cover 12 is provided such that the main surface 12a contacts the heat-generating component 13 such as the above-described CPU. In order to efficiently transfer heat from the heat generating component 13 to the cover 12, a heat conductive sheet may be provided between the cover 12 and the heat generating component 13.

  Further, in this example, a second heat generating component 20 such as a power supply IC different from the first heat generating component 13 is also fixed to the circuit board 16, and the second heat generating component 20 is also covered with the cover 12.

  Note that the second heat generating component 20 is omitted in FIG. 3 described above in order to avoid complication of the drawing.

  In addition, although a gap is formed between the main surface 12a of the cover 12 and the second heat generating component 20, the main surface 12a is provided to efficiently transfer heat from the second heat generating component 20 to the cover 12. You may make it dent and contact the 2nd heat-emitting component 20. FIG.

  The cover 12 and the loop heat pipe 1 are bonded to each other by the heat conductive sheet 21. Furthermore, the loop heat pipe 1 is provided so as to be in close contact with the above-described sheet metal 11.

  According to such a structure, it is considered that the heat generated in each of the heat generating components 13 and 20 can be cooled by the loop heat pipe 1.

  However, since the loop heat pipe 1 and the cover 12 are separate parts, the above-described heat conductive sheet 21 is required to bond them together. Then, due to the heat conductive sheet 21, extra heat resistance is generated in the path from each heat generating component 13, 20 to the loop heat pipe 1, and each heat generating component 13, 20 is cooled by the loop heat pipe 1. It becomes difficult to do.

  In addition, since the loop heat pipe 1 and the cover 12 are separate parts, a process of attaching them is necessary, and there is a problem that the manufacturing process of the electronic device 2 increases.

  Hereinafter, each embodiment that can reduce the thermal resistance between the loop heat pipe and the heat generating component will be described.

(First embodiment)
FIG. 5 is an exploded perspective view of the electronic apparatus according to the present embodiment.

  In FIG. 5, the same elements as those described in FIG. 3 are denoted by the same reference numerals as those in FIG. 3, and the description thereof is omitted below.

  The electronic device 30 is a mobile electronic device such as a smartphone, and includes a lower housing 14 and an upper housing 15.

  The lower housing 14 accommodates a circuit board 16 to which the heat generating components 13 and 20 are fixed. As described above, the first heat generating component 13 is, for example, a CPU, and the second heat generating component 20 is, for example, a power supply IC.

  In order to cool these heat generating components 13 and 20, a loop heat pipe 31 is provided in the electronic device 30.

  The loop heat pipe 31 includes a metal cover 37 above the heat generating components 13 and 20 and an evaporator 33 that vaporizes the working fluid by the heat of the heat generating components 13 and 20.

  FIG. 6 is a perspective view of the electronic device 30 during assembly.

  As shown in FIG. 6, the loop heat pipe 31 is fixed on the circuit board 16 during assembly. The fixing method is not particularly limited, but in this example, the loop heat pipe 31 is screwed to the circuit board 16 using the holes 33b at the four corners of the evaporator 33.

  The heat generating components 13 and 20 are covered with the cover 37 of the loop heat pipe 31. The cover 37 can shield the heat generating components 13 and 20 electromagnetically or protect the heat generating components 13 and 20 from an external mechanical shock.

  FIG. 7 is a perspective view of the loop heat pipe 31.

  The loop heat pipe 31 has a condenser 34. A vapor pipe 35 and a liquid pipe 36 are connected to the evaporator 33 and the condenser 34, and a loop-like flow path through which the working fluid C flows is formed by these pipes 35 and 36.

  The working fluid C is guided from the liquid pipe 36 to the evaporator 33 and is vaporized by each of the heat generating components 13 and 20 described above. The vapor Cv of the working fluid C generated by the evaporator 33 is guided to the condenser 34 through the vapor pipe 35, and is cooled and liquefied again in the condenser 34.

  The size of the loop heat pipe 31 is not particularly limited, but it is preferable that the size of the loop heat pipe 31 be small enough to be accommodated in a mobile electronic device such as a smartphone. For example, it is preferable to design the size of the loop heat pipe 31 so as to circumscribe a rectangle having a short side of 60 mm and a long side of about 90 mm.

  8 is a cross-sectional view taken along the line II-II in FIG.

  As shown in FIG. 8, the loop heat pipe 31 is formed by laminating a first metal layer 38 and a second metal layer 39.

  The second metal layer 39 is a metal layer having a Young's modulus higher than that of the first metal layer 38, and is a stainless steel layer made of SUS304 having a thickness of 0.1 mm, for example. Note that an aluminum layer may be adopted as the second metal layer 39 instead of the stainless steel layer. The same applies to each embodiment described later.

  On the other hand, the first metal layer 38 is a metal layer having a higher thermal conductivity than the second metal layer 39, and is a copper layer having a thickness of 0.1 mm, for example.

  In this example, a second metal layer 39 is disposed on the uppermost layer and the lowermost layer of the loop heat pipe 31, and a plurality of first metal layers 38 are provided between the second metal layers 39. The metal layers 38 and 39 are joined to each other by diffusion bonding, and a flow path 38a through which the working fluid C flows is defined by the metal layers 38 and 39.

  Such a flow path 38 a is defined not only in the vapor pipe 35 but also in the evaporator 33, the condenser 34, and the liquid pipe 36.

  Further, when six metal layers 38 and 39 each having a thickness of about 0.1 mm are laminated as in this example, the loop heat pipe 31 can be thinned to a thickness of about 0.6 mm. Thereby, it becomes possible to push forward thickness reduction of the electronic devices 30 (refer FIG. 5), such as a smart phone.

  The first metal layer 38 in the evaporator 33 (see FIG. 7) is provided with a plurality of holes 38k having a diameter of about 0.2 mm. The capillary force acting on the liquid-phase working fluid C from these holes 38k serves as a pumping force for circulating the working fluid C in one direction in the loop heat pipe 31.

  Next, a method for manufacturing the loop heat pipe 31 according to this embodiment will be described.

  FIGS. 9A and 9B are side views in the middle of manufacturing the loop heat pipe 31 according to the present embodiment.

  First, as shown in FIG. 9A, the above-described second metal layer 39 such as a stainless steel layer is disposed on the uppermost layer and the lowermost layer, and the first metal layer 38 such as a copper layer is interposed between them. Arrange multiple. The number of first metal layers 38 is not particularly limited. For example, four first metal layers 38 can be stacked.

  Then, as shown in FIG. 9B, by pressing the metal layers 38 and 39 while heating the metal layers 38 and 39 to about 900 ° C., the metal layers 38 and 39 are mutually bonded by diffusion bonding. Join.

  FIG. 10 is a plan view of the laminate obtained by laminating the metal layers 38 and 39 as viewed from the second metal layer 39 as the uppermost layer.

  As shown in FIG. 10, the uppermost second metal layer 39 has a first folding margin 39 x beside the evaporator 33. The first folding margin 39x is formed in an elongated shape by extending one side of the rectangular evaporator 33 in plan view.

  Further, an extension 41 is provided beside the evaporator 33. The extension 41 is formed of a first metal layer 38 and a second metal layer 39 that extend to the side of the evaporator 33.

  In this example, the number of the first metal layers 38 is four as described above, but it is not necessary to draw all of the first metal layers 38 to the extension portion 41. For example, only one layer of the first metal layer 38 immediately below the uppermost second metal layer 39 can be drawn out to the extension 41.

  The uppermost second metal layer 39 is provided with an opening 39a, and the first metal layer 38 is exposed from the opening 39a.

  The extension part 41 is substantially rectangular in plan view, and a second folding allowance 41x is provided on each of the four sides. The second folding allowance 41x is formed only of the second metal layer 39 having high mechanical strength among the first metal layer 38 and the second metal layer 39 forming the extension portion 41.

  FIG. 11 is a perspective view of a laminate of the first metal layer 38 and the second metal layer 39 formed as described above.

  As shown in FIG. 11, at the four corners of the evaporator 33, protrusions 33a protruding in the lateral direction of the evaporator 33 are provided, and screw holes 33b are formed in the protrusions 33a.

  As shown in the dotted circle, the first folding margin 39x described above is formed below the protruding portion 33a, but the protruding portion 33a and the first folding margin 39x are not joined. In order to prevent only a part of each of the metal layers 38 and 39 from being joined in this way, for example, in the above-described diffusion joining, a spacer S such as a Teflon (registered trademark) plate is inserted into the part, and in that part, The constituent atoms of the metal layers 38 and 39 may be prevented from diffusing with each other.

  The subsequent steps will be described with reference to FIGS.

  FIGS. 12-14 is a perspective view in the middle of manufacture of the loop type heat pipe which concerns on this embodiment.

  First, as shown in FIG. 12, the long first folding margin 39x is bent by an angle of 90 ° with the long side 39y as a folding line.

  Further, as shown in FIG. 13, the second folding allowance 41x is also bent by an angle of 90 ° with the long side 41y as a folding line.

  Subsequently, as shown in FIG. 14, the first folding margin 39x is bent at an angle of 90 ° in the vicinity of the protruding portion 33a.

  The basic structure of the loop heat pipe 31 according to the present embodiment is completed through the steps so far.

  Thereafter, water is injected as the working fluid C from the inlet 31a into the liquid pipe 35 of the loop heat pipe 31, and then the inlet 31a is sealed.

  FIG. 15 is a perspective view of a loop heat pipe 31 in which the front and back sides of FIG. 14 are reversed.

  As shown in FIG. 15, the side surface 37a of the cover 37 is formed by the first folding allowance 39x and the second folding allowance 41x. The main surface 37 b of the cover 37 is formed by the uppermost second metal layer 39 and the first metal layer 38 exposed from the opening 39 a of the second metal layer 39.

  Then, the first heat generating component 13 and the second heat generating component 20 are pasted on the main surface 37b via a heat conductive sheet (not shown), whereby the heat generating components 13, 20 and the cover 37 are heated. Will come into contact.

  In this way, by folding one of the plurality of metal layers 38 and 39 to form the cover 37, a heat conductive sheet or the like for thermally connecting the cover 37 and the loop heat pipe 31 becomes unnecessary. Therefore, thermal resistance due to the heat conductive sheet or the like does not occur, and the thermal resistance between the cover 37 and the loop heat pipe can be reduced.

  In addition, since it is not necessary to facilitate the cover 37 as a separate part, the manufacturing process of the loop heat pipe 31 can be simplified.

  16 is a cross-sectional view taken along line III-III in FIG.

  As shown in FIG. 16, the first heat generating component 13 is in contact with the second metal layer 39 corresponding to the evaporator 33. Thereby, the working fluid C in the evaporator 33 is vaporized by the heat of the first heat generating component 13, and the first heat generating component 13 can be cooled by the heat of vaporization.

  On the other hand, the second heat-generating component 20 such as a power supply IC is in contact with the first metal layer 38 exposed from the opening 39a.

  The second heat generating component 20 is provided in the extension portion 41 of the evaporator 33, but the thermal conductivity of the first metal layer 38 such as a copper layer is higher than that of the second metal layer 29 such as a stainless steel layer. The heat of the second heat generating component 20 is quickly transmitted to the evaporator 33 through the first metal layer 38. As a result, the second heat generating component 20 can be satisfactorily cooled by the evaporator 33, and insufficient cooling of the second heat generating component 20 can be prevented.

  Furthermore, in this embodiment, a stainless steel layer having a Young's modulus higher than that of the first metal layer 38 is employed as the second metal layer 39, and the side surface 37a of the cover 37 is formed by the second metal layer 39. The side surface 37a surrounds the heat generating components 13 and 20. Thereby, the strength of the cover 37 is increased, and it becomes easy to protect the heat generating components 13 and 20 from mechanical impact.

  If priority is given to the thermal conductivity of the cover 37 over the strength of the cover 37, the first metal having good thermal conductivity such as a copper layer is used without using the two metal layers 38 and 39 in this way. The cover 37 may be formed of only the layer 38.

  Although the present embodiment has been described in detail above, the present embodiment is not limited to the above. For example, in the above description, the cover 37 and the heat generating components 13 and 20 are brought into contact with each other. However, a heat conductive member is provided between the heat generating components 13 and 20 and the cover 37, and the heat generating components 13 and 20 are connected to the cover 37. You may make it contact | connect thermally.

  Further, the side surface 37 a may be formed by two or more of the metal layers 38 and 39.

(Second Embodiment)
In the present embodiment, the strength of the cover 37 is further increased than in the first embodiment.

  FIG. 17 is a cross-sectional view of the evaporator 33 provided in the loop heat pipe according to the present embodiment and the vicinity thereof.

  In FIG. 17, the same elements as those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted below.

  As shown in FIG. 17, in this embodiment, a reinforcing plate 39 z formed by bending a second metal layer 39 is provided between the first heat generating component 13 and the second heat generating component 20.

  The strength of the cover 37 is increased by the reinforcing plate 39z, and it becomes easy to protect the heat generating components 13 and 20 with the cover 37.

  Below, the method to provide the reinforcement board 39z is demonstrated.

  FIG. 18 is a partial plan view of the second metal layer 39 according to the present embodiment.

  As shown in FIG. 18, a linear cut 39w is formed in advance in the second metal layer 39, and one side of the long reinforcing plate 39z is defined by the cut 39w.

  FIGS. 19A and 19B are perspective views schematically showing a method of providing the reinforcing plate 39z.

  First, as shown in FIG. 19A, the reinforcing plate 39z is bent at an angle of 90 ° with the short side 39f of the long reinforcing plate 39z as a folding line.

  Next, as shown in FIG. 19B, the reinforcing plate 39x is bent at an angle of 90 ° with the extended line 39g of the cut 39w (see FIG. 18) as a fold line.

  As described above, a structure in which the reinforcing plate 39z is erected on the second metal layer 39 is obtained.

(Third embodiment)
In the present embodiment, the first heat generating component 13 can be effectively cooled as follows.

  FIG. 20 is an enlarged cross-sectional view of the metal layer 40 used in the present embodiment.

  The metal layer 40 is an inlay clad material obtained by bonding the first metal layer 38 and the second metal layer 39 together in the same layer. As in the first embodiment, the first metal layer 38 is, for example, a copper layer, and the second metal layer 39 is, for example, a stainless steel layer.

  FIG. 21 is a cross-sectional view of the evaporator 33 of the loop heat pipe according to the present embodiment employing such a metal layer 40 and the vicinity thereof.

  In FIG. 21, the same elements as those described in the first embodiment and the second embodiment are denoted by the same reference numerals as those in these embodiments, and the description thereof is omitted below.

  As shown in FIG. 21, in this embodiment, the metal layer 40 is used for the resurfaced layer of the evaporator 33 and the layer thereon. Then, each of the first heat generating component 13 and the second component 20 is provided in contact with the first metal layer 38 in the metal layer 40.

  As a result, the first heat generating component 13 can be cooled by the evaporator 33 via the first metal layer 38 such as a copper layer having a higher thermal conductivity than the second metal layer 39 such as a stainless steel layer. The cooling efficiency of the first heat generating component 13 is higher than that of the form.

  Similarly to the first embodiment, the side surface 37a of the cover 37 is formed by the second metal layer 39 having a Young's modulus higher than that of the first metal layer 38, whereby the strength of the cover 37 can be increased. .

  In addition, this embodiment is not limited to the above, You may provide the reinforcement board 39z (refer FIG. 17) between the 1st heat generating component 13 and the 2nd heat generating component 20 similarly to 3rd Embodiment.

(Fourth embodiment)
FIG. 22 is an exploded perspective view of the electronic apparatus according to the present embodiment.

  In FIG. 22, the same elements as those described in the first to third embodiments are denoted by the same reference numerals as those in these embodiments, and the description thereof is omitted below.

  The electronic device 50 is a mobile electronic device such as a smartphone as in the first embodiment, and includes a lower housing 14, an upper housing 15, and a loop heat pipe 51.

  The loop heat pipe 51 according to this embodiment includes a second metal layer that is a resurfacing layer near the upper housing 15 among the plurality of metal layers 38 and 39 that form the loop heat pipe 31 according to the first embodiment. 39 is solid. As a result, the second metal layer 39 is provided in all regions inside the loop formed by the evaporator 33, the condenser 34, the vapor pipe 35, and the liquid pipe 36.

  Thus, by making the second metal layer 39 solid, the loop heat pipe 51 also functions to shield external electromagnetic waves that try to enter the heat generating components 13 and 20 from the upper housing 15 side. It will be. Therefore, it is not necessary to provide the sheet metal 11 (see FIG. 3) in order to ensure this function, and the manufacturing process of the electronic device 50 can be simplified as compared with the case where the sheet metal 11 is provided.

  In addition, since the heat of the loop heat pipe 51 diffuses in the plane of the solid second metal layer 39, temperature unevenness hardly occurs inside the electronic device 50, and the temperature of each part of the electronic device 50 is made uniform. Can be made easier.

(Fifth embodiment)
In the first embodiment, as shown in FIG. 16, the extension portion 41 is provided in the evaporator 33, and the second heat generating component 20 is covered with the extension portion 41.

  In contrast, a case where the second heat generating component 20 is not provided and the extension 41 is omitted will be described below.

  FIG. 23 is an exploded perspective view of the electronic device 70 according to the present embodiment.

  In FIG. 23, the same elements as those described in the first to fourth embodiments are denoted by the same reference numerals as those in these embodiments, and the description thereof is omitted below.

  The electronic device 70 is a smartphone, for example, and accommodates the loop heat pipe 60. In the loop heat pipe 60, the extension 41 (see FIG. 15) is not provided, and only the first electronic component 13 is covered with the cover 37.

  Similarly to the first embodiment, the loop heat pipe 60 can also be manufactured by laminating the first metal layer 38 and the second metal layer 39 in this embodiment.

  Next, a method for manufacturing the loop heat pipe 60 according to the present embodiment will be described.

  FIG. 24 is a plan view of a laminated body obtained by laminating the metal layers 38 and 39 in this embodiment as viewed from the uppermost second metal layer 39.

  As shown in FIG. 24, the uppermost second metal layer 39 has a first folding margin 39 x beside the evaporator 33.

  The subsequent steps will be described with reference to FIGS.

  25 to 27 are perspective views in the middle of manufacturing the loop heat pipe according to the present embodiment.

  First, as shown in FIG. 25, the second metal layer 39 at the peripheral edge of the evaporator 33 is bent upward by an angle of 90 °.

  Then, as shown in FIG. 26, the first folding margin 39x is bent by an angle of 90 ° with the long side 39y as a folding line.

  Further, as shown in FIG. 27, the cover 37 is formed by bending the first folding margin 39x by an angle of 90 ° in the vicinity of the protruding portion 33a.

  Thus, the basic structure of the loop heat pipe 60 is completed.

  The following additional notes are disclosed for each embodiment described above.

(Appendix 1) An evaporator that is in thermal contact with the first heat generating component and vaporizes the working fluid by the heat of the first heat generating component;
A condenser for liquefying the working fluid;
A liquid pipe connecting the evaporator and the condenser;
A vapor pipe connecting the evaporator and the condenser and forming a loop with the liquid pipe;
A loop heat pipe, wherein the evaporator is formed by laminating a plurality of metal layers, and at least one of the plurality of metal layers is bent to cover the first heat-generating component.

(Supplementary Note 2) The plurality of metal layers include a first metal layer and a second metal layer having a Young's modulus higher than that of the first metal layer,
The loop heat pipe according to appendix 1, wherein the cover is formed by bending the second metal layer.

  (Additional remark 3) The said 1st metal layer has the extension part extended to the side of the said evaporator, and a 2nd heat-emitting component contacts the said 1st metal layer exposed to this extension part thermally. The loop heat pipe as set forth in Appendix 2, wherein

  (Supplementary note 4) The loop according to supplementary note 3, wherein a reinforcing plate formed by bending the second metal layer is provided between the first heat-generating component and the second heat-generating component. Type heat pipe.

  (Supplementary Note 5) The first metal layer and the second metal layer are joined to each other in the same layer, and the first heat-generating component is in thermal contact with the first metal layer. The loop-type heat pipe according to Supplementary Note 2, which is characterized.

  (Supplementary note 6) The loop heat pipe according to any one of supplementary notes 2 to 5, wherein the first metal layer has higher thermal conductivity than the second metal layer.

  (Supplementary note 7) The loop heat pipe according to supplementary note 6, wherein the material of the first metal layer is copper, and the material of the second metal layer is stainless steel.

(Appendix 8) The cover is
A main surface with which the first heat-generating component contacts;
The loop heat pipe according to claim 1, further comprising a side surface that is formed of the bent metal layer and surrounds the periphery of the first heat-generating component.

  (Supplementary note 9) The loop heat pipe according to any one of supplementary notes 1 to 8, wherein at least one of the plurality of metal layers is provided in all regions inside the loop.

(Appendix 10)
A loop heat pipe for cooling the heat generating component;
The loop heat pipe is
An evaporator that is in thermal contact with the heat generating component and vaporizes the working fluid by the heat of the heat generating component;
A condenser for liquefying the working fluid;
A liquid pipe connecting the evaporator and the condenser;
A vapor pipe that connects the evaporator and the condenser and forms a loop with the liquid pipe;
An electronic apparatus, wherein the evaporator is formed by laminating a plurality of metal layers, and at least one of the plurality of metal layers is bent to cover the heat generating component.

(Appendix 11)
Forming each of an evaporator, a condenser, a liquid pipe, and a steam pipe by laminating a plurality of metal layers;
Forming a cover that covers a heat-generating component in thermal contact with the evaporator by bending at least one of the plurality of metal layers in the evaporator;
Injecting a working fluid into the liquid pipe;
A method for manufacturing a loop heat pipe, comprising:

DESCRIPTION OF SYMBOLS 1, 31, 51, 60 ... Loop type heat pipe 2, 30 ... Electronic equipment 3, 33 ... Evaporator 4, 34 ... Condenser 5, 35 ... Steam pipe, 6, 36 ... Liquid pipe, 7 ... Copper layer, 7a ... flow path, 11 ... sheet metal, 12, 37 ... cover, 12a ... main surface, 13 ... first heating component, 14 ... lower housing, 15 ... upper housing, 16 ... circuit board, 17 ... Batteries 18 ... frame 19 ... clad material 20 ... second heat generating component 21 ... heat transfer sheet 31a ... inlet, 33a ... projection, 33b ... hole, 37a ... side, 37b ... main surface, 38 ... 1st metal layer, 38a ... flow path, 39 ... 2nd metal layer, 39f ... short side, 39g ... extension line, 39x ... 1st folding allowance, 39y ... long side, 39z ... reinforcing plate, 40 ... metal Layer, 41 ... extension, 41x ... second folding allowance, 41y ... long side.

Claims (5)

An evaporator that is in thermal contact with the first heat generating component and vaporizes the working fluid by the heat of the first heat generating component;
A condenser for liquefying the working fluid;
A liquid pipe connecting the evaporator and the condenser;
A vapor pipe connecting the evaporator and the condenser and forming a loop with the liquid pipe;
A loop heat pipe, wherein the evaporator is formed by laminating a plurality of metal layers, and at least one of the plurality of metal layers is bent to cover the first heat-generating component. The plurality of metal layers include a first metal layer and a second metal layer having a higher Young's modulus than the first metal layer,
The loop heat pipe according to claim 1, wherein the cover is formed by bending the second metal layer.   The loop heat pipe according to claim 2, wherein the first metal layer has a higher thermal conductivity than the second metal layer. Heat-generating parts,
A loop heat pipe for cooling the heat generating component;
The loop heat pipe is
An evaporator that is in thermal contact with the heat generating component and vaporizes the working fluid by the heat of the heat generating component;
A condenser for liquefying the working fluid;
A liquid pipe connecting the evaporator and the condenser;
A vapor pipe that connects the evaporator and the condenser and forms a loop with the liquid pipe;
An electronic apparatus, wherein the evaporator is formed by laminating a plurality of metal layers, and at least one of the plurality of metal layers is bent to cover the heat generating component. Forming each of an evaporator, a condenser, a liquid pipe, and a steam pipe by laminating a plurality of metal layers;
Forming a cover that covers a heat-generating component in thermal contact with the evaporator by bending at least one of the plurality of metal layers in the evaporator;
Injecting a working fluid into the liquid pipe;
A method for manufacturing a loop heat pipe, comprising:

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