Manufacturing method

Abstract

To produce a heat exchanger etc. in which a dimension is reduced in a thickness direction.SOLUTION: A manufacturing method of the invention manufactures a heat exchanger which has an evaporating body which absorbs heat from the exterior and evaporates working fluid in a liquid phase into a gas phase while moving the working fluid in the liquid phase with capillary force. The manufacturing method includes: a step in which a recessed part is formed on a plate surface of a first plate member, a plate-like member; a step in which a material containing a powder is applied to a predetermined area in the recessed part; a step in which the material applied to the predetermined area is solidified to form the evaporating body; and a step in which the recessed part provided with the evaporating body is covered with a second plate member, a plate-like member, to fix the first plate member to the second plate member.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a manufacturing method.

Background Art

[0002] Patent Document 1 discloses a loop heat pipe provided with wicks that generate capillary force and are respectively provided inside an evaporation section, a condensation section, and a liquid return pipe in order to efficiently cool a heat generating component regardless of the installation angle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in recent years, with the miniaturization and high performance of devices such as electronic devices, the heat generation density of heat generating bodies provided in the devices has been increasing. And, for example, with the thinning of the device, there is a demand for a heat exchanger or the like that removes the heat flux from the heat generating body while suppressing the dimensions in the thickness direction. Therefore, an object of the present invention is to manufacture a heat exchanger or the like in which the dimensions in the thickness direction are suppressed.

Means for Solving the Problems

[0005] To achieve the above object and solve the above problems, the following inventions are provided as means. That is, the invention according to claim 1 is a manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a liquid-phase working fluid into a gas phase while moving it by capillary force, including a step of forming a recess on the plate surface of a first plate member that is a plate-shaped member, a step of applying a material containing powder to a predetermined region in the recess, a step of solidifying the material applied to the predetermined region to form the evaporator, and a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member and fixing the first plate member and the second plate member. See, the heat exchanger includes a joint portion provided between the second plate member and the evaporator and joining the second plate member and the evaporator so as to suppress the flow of a fluid in the liquid phase. It is a manufacturing method. The invention according to claim 2 is the manufacturing method according to claim 1, including a step of arranging a covering member provided with holes for passing the material in the shape of the predetermined region on the surface covering the first plate member on the first plate member, and a step of applying the material through the holes of the covering member. The invention according to claim 3 is the manufacturing method according to claim 2, wherein the evaporator has a substrate extending in a direction intersecting the direction in which the liquid-phase working fluid in the evaporator moves, and a plurality of downflow bodies located on the downstream side in the moving direction from the substrate, and the holes are in a shape corresponding to the substrate and the plurality of downflow bodies. The invention according to claim 4 is the manufacturing method according to claim 2 or 3, wherein the covering member has different thicknesses according to the position in the direction in which the liquid-phase working fluid in the evaporator moves. The invention according to claim 5 is the manufacturing method according to any one of claims 1 to 4, wherein the material applied to the predetermined region contacts the inner side surface of the recess at both ends in a direction intersecting the direction in which the liquid-phase working fluid moves in the evaporator. Claim 6 The invention described in is the manufacturing method according to any one of claims 1 to 5 wherein the thickness of the material applied in the step of applying the material becomes thinner as it advances to the downstream side in the direction in which the liquid-phase working fluid moves in the evaporator. Claim 7The invention described in [claim number] includes a step of pressing a part of the region of the material applied to the predetermined region, from claim 1 to 6 The manufacturing method according to any one of [claim numbers]. Claim 8 In the invention described in [claim number], the step of forming the recess forms the recess by etching the plate surface of the first plate member, from claim 1 to 7 The manufacturing method according to any one of [claim numbers]. The invention according to claim 9 is a manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a working fluid in the liquid phase into the gas phase while moving the working fluid in the liquid phase by capillary force. The method includes a step of forming a recess on a plate surface of a first plate member that is a plate-shaped member, a step of applying a material containing powder to a predetermined region in the recess, a step of hardening the material applied to the predetermined region to form the evaporator, and a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member and fixing the first plate member and the second plate member. The material applied to the predetermined region contacts the inner side surface of the recess at both ends in a direction intersecting with the direction in which the working fluid in the liquid phase moves inside the evaporator. The material applied to the predetermined region is separated from the inner side surface of the recess on the upstream side in the moving direction compared to the portion in contact with the inner side surface of the recess. Manufacture Manufacturing method. The invention according to claim 10 is a manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a working fluid in the liquid phase into the gas phase while moving the working fluid in the liquid phase by capillary force. The method includes a step of forming a recess on a plate surface of a first plate member that is a plate-shaped member, a step of applying a material containing powder to a predetermined region in the recess, a step of hardening the material applied to the predetermined region to form the evaporator, and a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member and fixing the first plate member and the second plate member. The step of applying the material includes a first application step of applying a first material and a second application step of applying a second material on top of the first material. Depending on the position in the direction in which the working fluid in the liquid phase in the evaporator moves, the thicknesses of the first material and the second material are different. Manufacture Manufacturing method. The invention according to claim 11 is a manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a working fluid in the liquid phase into the gas phase while moving the working fluid in the liquid phase by capillary force. The method includes a step of forming a recess on a plate surface of a first plate member that is a plate-shaped member, a step of applying a material containing powder to a predetermined region in the recess, a step of hardening the material applied to the predetermined region to form the evaporator, and a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member and fixing the first plate member and the second plate member, The step of applying the material at a position other than the predetermined region in the flow path of the working fluid and is included. In the step of forming the evaporator, the material applied to the other position is sintered to form a sintered body, and the sintered body is sandwiched between the first plate member and the second plate member at the other position. Manufacture Manufacturing method. The invention according to claim 12 is a manufacturing method for manufacturing an apparatus provided with a heat generating component and a heat exchanger having an evaporator that absorbs heat from the heat generating component and evaporates the working fluid in the liquid phase into the gas phase while moving it by capillary force. The method includes a step of forming a recess in the plate surface of a first plate member that is a plate-shaped member, a step of applying a material containing powder to a predetermined region in the recess, a step of solidifying the material applied to the predetermined region to form the evaporator, a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member, and fixing the first plate member and the second plate member, and a step of fixing the heat generating component to at least one of the first plate member and the second plate member. See, the heat exchanger includes a joint portion provided between the second plate member and the evaporator and joining the second plate member and the evaporator so as to suppress the flow of a fluid in the liquid phase. Manufacturing method.

Advantages of the Invention

[0006] According to the invention described in claim 1, a heat exchanger with suppressed dimensions in the thickness direction can be manufactured. According to the invention described in claim 2, the arrangement of materials becomes easier. According to the invention described in claim 3, the formation of the evaporator becomes easier. According to the invention described in claim 4, the thickness change of the evaporator becomes easier. According to the invention described in claim 5, the formation of a gap between the evaporator and the recess is suppressed. Claim 6 According to the described invention, the design of the evaporator becomes easier. Claim 7 According to the described invention, a part of the region of the evaporator can have an average opening diameter different from that of other regions. Claim 8 According to the described invention, the evaporator is securely fixed by the first plate member. Claim 9 According to the described invention, the liquid-phase working fluid is easily guided to the evaporator. Claim 10 According to the described invention, the design of the evaporator becomes easier. Claim 11 According to the described invention, deformation of the first plate member and the second plate member can be suppressed. According to the invention described in claim 12, an apparatus with suppressed dimensions in the thickness direction can be manufactured.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0008] Hereinafter, with reference to the accompanying drawings, this embodiment will be described in detail. <First Embodiment> <Schematic Configuration of Loop Heat Pipe 100> FIG. 1 is a schematic configuration diagram showing a loop heat pipe 100 according to this embodiment. First, with reference to FIG. 1, the configuration of the loop heat pipe 100 to which this embodiment is applied will be described. The loop heat pipe 100 to which this embodiment is applied is a heat exchanger, and is configured to circulate a working fluid in order to cool a heat generating body 10 such as a central processing unit (CPU) provided in, for example, an electronic device or the like, without supplying power from the outside.

[0009] Specifically, the loop heat pipe 100 has an evaporator 101 that evaporates a working fluid in order to cool the heat generating body 10 by using the latent heat when the working fluid vaporizes, and a condenser 107 that dissipates heat from the working fluid vaporized in the evaporator 101 and liquefies it.

[0010] The loop heat pipe 100 also includes a vapor line 105 that sends the working fluid vaporized in the evaporator 101 to the condenser 107, and a liquid line 109 that sends the working fluid liquefied in the condenser 107 to the evaporator 101. The loop heat pipe 100 is filled with a working fluid that undergoes a phase change between the liquid phase and the gas phase. Note that, for example, water, alcohol, ammonia, etc. are used as the working fluid.

[0011] <Operation of the loop heat pipe 100> Next, with reference to FIG. 1, the operation within the loop heat pipe 100 will be described. The heat generated in the heating element 10 is transmitted to the evaporator 101 (see arrow H1). The working fluid that has absorbed heat in the evaporator 101 vaporizes and is sent to the condenser 107 via the vapor line 105 (see arrow A1) (see arrow A2). The working fluid sent to the condenser 107 releases heat (see arrow H2) and liquefies. Then, the liquefied working fluid is sent back to the evaporator 101 via the liquid line 109 (see arrow A3) (see arrow A4). In this way, the loop heat pipe 100 is a passive fluid device and a two-phase heat transfer device that uses the capillary force of the fluid as the driving source.

[0012] <Detailed configuration of the loop heat pipe 100> FIG. 2 is an exploded perspective view of the loop heat pipe 100. FIG. 3 is a detailed configuration diagram of the first side plate 111 and the second side plate 121. Next, with reference to FIGS. 2 and 3, the detailed configuration of the loop heat pipe 100 to which the present embodiment is applied will be described.

[0013] As shown in FIG. 2, the loop heat pipe 100 according to the present embodiment is generally flat-plate shaped. The loop heat pipe 100 includes a first side plate 111 and a second side plate 121, each having a generally flat-plate shape, and a wick 130 and a bonding material 150, each having a generally flat-plate shape, provided between the first side plate 111 and the second side plate. That is, the loop heat pipe 100 is configured such that the wick 130 and the bonding material 150 are sandwiched by the first side plate 111 and the second side plate 121.

[0014] The first side plate 111 has a first outer surface 113 and a first inner surface 115, each having a generally rectangular shape when viewed from the front. The first side plate 111 also has a first through hole 1129 formed through the plate surface. The second side plate 121 has a second inner surface 123 and a second outer surface 125, each having a generally rectangular shape when viewed from the front. The second side plate 121 also has a second through hole 1229 formed through the plate surface. The first side plate 111 and the second side plate 121 are formed of a metal material such as copper, for example. And the wick 130 and the bonding material 150 are disposed between the first inner surface 115 of the first side plate 111 and the second inner surface 123 of the second side plate 121.

[0015] Here, the loop heat pipe 100 enables heat diffusion using the first side plate 111 and the second side plate 121, i.e., the housing. Also, the loop heat pipe 100 is generally formed in a flat-plate shape with a thickness of, for example, 1 mm or less. Further, the loop heat pipe 100 is formed in dimensions that can be provided, for example, in a smartphone. Specifically, the loop heat pipe 100 is formed in dimensions such that, for example, the overall length is 100 mm, the width is 60 mm, and the thickness is 0.3 mm or less. To further explain, the loop heat pipe 100 is formed with a thickness of, for example, 3% or less, more preferably 1% or less, of the dimension in the plane direction (e.g., length or width).

[0016] In the following description, the thickness direction of the loop heat pipe 100, that is, the vertical direction in FIG. 2, may be simply referred to as the thickness direction. Also, the lower side in the vertical direction in FIG. 2 may be referred to as the first surface side, and the upper side in FIG. 2 may be referred to as the second surface side. Further, the direction in which the working fluid is transferred in the wick 130, that is, the direction extending between the upper left and lower right in FIG. 2, may be simply referred to as the transfer direction. Also, the upper left side in FIG. 2 may be referred to as the upstream side, and the lower right side may be referred to as the downstream side. Further, the direction orthogonal to the vertical direction and the transfer direction in FIG. 2 may be referred to as the width direction. Also, the front left side of the paper surface in the width direction in FIG. 2 may be referred to as one side, and the back right side of the paper surface in the width direction may be referred to as the other side.

[0017] Now, as shown in FIG. 3(a), a first recess 110 is formed in the first inner surface 115 of the first side plate 111. The first recess 110 is an annular region formed on the outer periphery of the first through hole 1129 in the first inner surface 115. More specifically, the first recess 110 has a first evaporator region 112, a first vapor pipe region 116, a first condenser region 117, a first liquid pipe region 118, and a first opening region 119, which are provided continuously in an annular shape.

[0018] Also, as shown in FIG. 3(b), a second recess 120 is formed in the second inner surface 123 of the second side plate 121. This second recess 120 is an annular region formed on the outer periphery of the second through hole 1229 in the second inner surface 123. Also, the second recess 120 has a shape that is mirror-symmetrical with the first recess 110. In other words, the first recess 110 and the second recess 120 are in a mirror-image relationship. More specifically, the second recess 120 has a second evaporator region 122, a second vapor pipe region 126, a second condenser region 127, a second liquid pipe region 128, and a second opening region 129, which are provided continuously in an annular shape.

[0019] Here, when the first inner surface 115 of the first side plate 111 and the second inner surface 123 of the second side plate 121 are combined, the first recess 110 and the second recess 120 are arranged to face each other. In this arrangement, the first evaporator region 112 and the second evaporator region 122 form the evaporator 101. Similarly, the first vapor pipe region 116 and the second vapor pipe region 126 form the vapor pipe 105. The first condenser region 117 and the second condenser region 127 form the condenser 107. The first liquid pipe region 118 and the second liquid pipe region 128 form the liquid pipe 109.

[0020] Note that the first opening region 119 and the second opening region 129 form openings that enable the injection of the working fluid into the first recess 110 and the second recess 120 from the outside after joining the first inner surface 115 of the first side plate 111 and the second inner surface 123 of the second side plate 121. Additionally, the openings formed by the first opening region 119 and the second opening region 129 are sealed after the injection of the working fluid.

[0021] Here, the first evaporator region 112 and the second evaporator region 122 that form the evaporator 101 will be described. First, the first evaporator region 112 is substantially rectangular in plan view. The first evaporator region 112 has a first wide region 1121 that is a space continuous with the first liquid pipe region 118, and a first narrow region 1123 that is a space downstream of the first wide region 1121 and continuous with the first vapor pipe region 116. Here, the first wide region 1121 and the first narrow region 1123 are arranged side by side in the transfer direction. Also, the first wide region 1121 has a larger dimension in the width direction compared to the first narrow region 1123.

[0022] Similarly, the second evaporator region 122 is substantially rectangular in plan view. The second evaporator region 122 has a second wide region 1221 that is a space continuous with the second liquid pipe region 128, and a second narrow region 1223 that is a space continuous with the second vapor pipe region 126 downstream of the second wide region 1221. Here, the second wide region 1221 and the second narrow region 1223 are arranged side by side in the transfer direction. Also, the second wide region 1221 has a larger dimension in the width direction compared to the second narrow region 1223.

[0023] Here, although details will be described later, a wick 130 is disposed inside the first evaporator region 112 and the second evaporator region 122. Inside the first evaporator region 112 and the second evaporator region 122, the space on the liquid pipe 109 side than the wick 130 functions as a liquid reservoir portion 160 in which the liquid-phase working fluid is accommodated. In the illustrated example, the first wide region 1121 and the second wide region 1221 constitute the liquid reservoir portion 160. Also, the space on the vapor pipe 105 side than the wick 130 in the first narrow region 1123 and the second narrow region 1223 functions as a vapor space 140 through which the gas-phase working fluid passes.

[0024] <Configuration around the wick 130> FIG. 4 is a diagram showing the configuration around the wick 130. Next, with reference to FIG. 4, the wick 130 and the configuration around the wick 130 will be described.

[0025] First, the wick 130 is formed of a porous body such as a porous metal (porous metal) formed of copper or the like. This wick 130 generates a capillary force in the working fluid and moves the working fluid. The effective pore diameter of the wick 130 is 0.1 to 50 μm. Also, the porosity of the wick 130 is 25 to 80%. Note that the measurement methods for the effective pore diameter and the porosity are not particularly limited. For example, it may be measured by apparent density measurement by the immersion method in water, pore diameter distribution measurement by mercury intrusion method, or pore observation by X-ray CT.

[0026] Incidentally, the wick 130 has dimensions such as a length in the width direction of 10 mm to 300 mm, a length in the transfer direction of 3 mm to 100 mm, and a thickness of 0.01 mm to 1 mm, more preferably a thickness of 0.1 mm to 0.5 mm. Further, the wick 130 is configured with dimensions such that the ratio of the thickness to the length in the width direction, that is, the length in the longitudinal direction, is about 0.01 to 1%, more preferably 0.1% to 0.5%. Note that the heating element 10 (see FIG. 1) has a width of 10 mm and a length of 10 mm, for example. And the wick 130 is configured with dimensions such that the width and length are larger than those of the heating element 10.

[0027] As shown in FIG. 4(a), the wick 130 has a substantially rectangular wick base portion 131 whose longitudinal direction is along the width direction, and a wick claw portion 133 that protrudes from the wick base portion 131 to the downstream side in the transfer direction. In the illustrated example, a plurality of wick claw portions 133 are provided at predetermined intervals in the width direction. In other words, the wick 130 includes a plurality of slits 135 formed along the transfer direction on the downstream side in the transfer direction. Note that the end portion on the upstream side in the transfer direction of the slit 135 is called the slit bottom portion 136. The wick claw portion 133 has a width direction length of 0.5 mm to 2.0 mm and a transfer direction length of 10 mm to 20 mm. The slit 135 has a width direction length of 0.5 mm to 2.0 mm, for example. Further explaining, the slit 135 has a longer (wider) width direction length than the wick claw portion 133. The slit 135 may have the same width direction length as the wick claw portion 133 or a different width direction length from the wick claw portion 133. Also, different from the illustrated example, the tip of the wick claw portion 133 and the slit bottom portion 136 may have a rounded (curved) shape.

[0028] Here, the wick 130 has a comb-like (rake-like) outline. The slit 135 formed in the wick 130 functions as a vapor groove, a so-called groove, that promotes the flow of the working fluid vaporized in the wick 130 toward the vapor pipe 105. To explain further, in the illustrated example, by alternately arranging the wick claw portions 133 and the slits 135 in the same plane, it is possible to maintain the mechanical strength while thinning the wick 130, the first side plate 111, and the second side plate 121. Also, by providing the wick claw portions 133 and the slits 135 in the same plane, the degree of freedom in arranging the heating element 10 (FIG. 1), which is the heat source, is improved. Specifically, the heating element 10 may be provided on either one or both of the first outer surface 113 of the first side plate 111 and the second outer surface 125 of the second side plate 121.

[0029] Now, the wick 130 is arranged across the first wide region 1121 and the first narrow region 1123 formed in the first side plate 111 in the transfer direction. To explain further, the wick 130 is arranged so as to protrude (project) from the first narrow region 1123 toward the first wide region 1121 side.

[0030] Also, the wick 130 is sandwiched between the narrow first side surface 1127 and the narrow second side surface 1128 in the first narrow region 1123. To explain further, the wick first side surface 138, which is the side surface of the wick 130 along the transfer direction, is joined to the narrow first side surface 1127 of the first side plate 111. Also, the wick second side surface 139 is joined to the narrow second side surface 1128 of the first side plate 111. Note that even when the material of the wick 130 shrinks at the stage of forming the wick 130 by sintering, as will be described later, the wick 130 is suppressed from separating from the narrow first side surface 1127 and the narrow second side surface 1128.

[0031] Also, the end face of the upstream end face 137 of the wick is located within the first wide region 1121. Along with this, the first side face 138 and the second side face 139 of the wick are exposed within the first wide region 1121. To explain further, the first side face 138 and the second side face 139 of the wick are separated from the wide first side face 1124 and the wide second side face 1125 of the first side plate 111 respectively. By this, the liquid-phase working fluid is allowed to flow into the wick 130 through the first side face 138 and the second side face 139 of the wick (see arrow C5 in Fig. 4(b)). By this, the area where the wick 130 contacts the liquid-phase working fluid increases, and the wetting of the wick 130 is improved.

[0032] Now, the wick 130 is arranged sandwiched between the first side plate 111 and the second side plate 121 as described above. Also, the wick 130 partitions the vapor space 140 and the liquid reservoir 160. Here, if a gap is formed between the first side plate 111 and the wick 130, or between the second side plate 121 and the wick 130, the liquid-phase working fluid may flow (leak) into the vapor space 140, or the gas-phase working fluid may flow into the liquid reservoir 160. And these inflows reduce the heat exchange rate of the loop heat pipe 100.

[0033] Therefore, in the present embodiment, a material to be the wick 130 is applied to the first inner surface 115 of the first side plate 111 to form the wick 130 on the first side plate 111 (described later). By this, it is suppressed that a gap is formed between the wick 130 and the first inner surface 115 of the first side plate 111. Also, in the present embodiment, the bonding material 150 is arranged on the wick 130 in an overlapping manner. By this, it is suppressed that a gap is formed between the wick 130 and the second inner surface 123 of the second side plate 121.

[0034] As shown in Fig. 4(b), the bonding material 150 has a bonding material base portion 151 that is substantially rectangular in shape with its longitudinal direction along the width direction, and a bonding material width-reduced portion 153 that protrudes downstream in the transfer direction from the bonding material base portion 151. This bonding material width-reduced portion 153 is substantially rectangular in shape with its longitudinal direction along the width direction, and its dimension in the width direction is narrower than that of the bonding material base portion 151. The bonding material 150 is a plate-like member made of metal formed of, for example, bronze.

[0035] Further, the bonding material 150 is provided at a position covering the wick base portion 131 of the wick 130. More specifically, the bonding material 150 is arranged to span the first wide region 1121 and the first narrow region 1123 in the transfer direction. Also, the bonding material 150 is formed to be sandwiched between the narrow first side surface 1127 and the narrow second side surface 1128 in the width direction. Further, the bonding material 150 is formed to be sandwiched between the wide first side surface 1124 and the wide second side surface 1125 in the width direction. Note that the upstream end surface 155 of the bonding material shown in the figure is provided flush with the upstream end surface 137 of the wick in the transfer direction. Here, the bonding material 150 is not particularly limited to the illustrated configuration as long as both ends are in contact with the narrow first side surface 1127 and the narrow second side surface 1128. For example, the bonding material 150 may not be in contact with the wide first side surface 1124 and the wide second side surface 1125 in the width direction. Also, the bonding material 150 may not be arranged to span the first wide region 1121 and the first narrow region 1123 in the transfer direction. Further, the upstream end surface 155 of the bonding material shown in the figure may not be provided flush with the upstream end surface 137 of the wick in the transfer direction.

[0036] Here, with reference to Fig. 4(b), the position of the downstream end surface 157 of the bonding material 150 in the transfer direction, which is the downstream end surface of the bonding material in the conveyance direction, will be described. The position of the downstream end surface 157 of the bonding material in the transfer direction is located between a virtual line L1 along the step surface 1126 formed between the wide first side surface 1124 and the narrow first side surface 1127, and a virtual line L2 along the slit bottom 136. Here, if the downstream end surface 157 of the bonding material is upstream of the virtual line L1 in the transfer direction, leakage of the working fluid may occur. Also, if the downstream end surface 157 of the bonding material is downstream of the virtual line L2 in the transfer direction, the function of the slit 135 may be reduced.

[0037] <Operation of Evaporator 101> Next, the operation inside the evaporator 101 will be described with reference to FIG. 4(a). First, the liquid-phase working fluid stored in the liquid reservoir portion 160 flows toward the wick 130 (see arrow C3) and penetrates into the wick 130. Then, the liquid-phase working fluid is heated by the heat of the heating element 10 and vaporizes while moving inside the wick 130 due to the capillary force of the wick 130.

[0038] This vaporized working fluid moves toward the vapor pipe 105 through the slit 135 or the like (see arrow C1), then flows out from the vapor pipe 105 and is sent to the condenser 107 (see FIG. 1). The working fluid liquefied in the condenser 107 (see FIG. 1) flows into the evaporator 101, penetrates into the wick 130 again through the liquid reservoir portion 160.

[0039] In this way, the above cycle is repeated without interruption of the flow of the working fluid in the wick 130. Then, the heat generated in the heating element 10 is transported from the evaporator 101 to the condenser 107 (see FIG. 1).

[0040] <Forming Process of the First Side Plate 111 and the Second Side Plate 121> As described above, the first side plate 111 and the second side plate 121 are formed by processing a flat member made of a metal material such as copper, for example, to form the first recess 110 and the second recess 120. In the illustrated example, an etching process is applied to a copper flat plate with a thickness of 0.15 mm to form the first recess 110 and the second recess 120. The depth of the first recess 110 and the second recess 120 is 0.1 mm. That is, the regions of the first side plate 111 and the second side plate 121 where the first recess 110 and the second recess 120 are formed have a thickness of 0.05 mm. Further explaining, by etching, more than 50% of the thickness of the first side plate 111 and the second side plate 121 is recessed. Also, around the outer shape of the first side plate 111 and the second side plate 121, through-etching, that is, outer copper plate etching, is performed so that the first side plate 111 and the second side plate 121 can be taken out. Also, in the illustrated example, by through-etching, a first through-hole 1129 is formed in the first side plate 111, and a second through-hole 1229 is formed in the second side plate 121.

[0041] <Formation process of wick 130 and bonding material 150> Next, with reference to FIG. 4, the formation process of the wick 130 and the bonding material 150 will be described.

[0042] In the present embodiment, the wick 130 and the bonding material 150 are formed on the first side plate 111 and the second side plate 121, respectively. Then, after overlapping the first side plate 111 on which the wick 130 is formed and the second side plate 121 on which the bonding material 150 is formed, the wick 130 and the bonding material 150 are fixed to each other.

[0043] Here, the illustrated wick 130 is formed on the first side plate 111 by applying the material of the wick 130 to the first side plate 111. Further explaining, the wick 130 is formed by applying a metal paste containing pure copper powder to a predetermined region in the first wide region 1121 and the first narrow region 1123 of the first side plate 111. Although details will be described later, when applying the wick 130, a mask 180 (see FIG. 5 described later) is used.

[0044] Further, the illustrated bonding material 150 is formed on the second side plate 121 by applying the material of the bonding material 150 to the second side plate 121. To explain further, the bonding material 150 is formed by applying a metal paste containing bronze powder to a predetermined area in the second wide area 1221 and the second narrow area 1223 of the second side plate 121. Here, masking is performed by a well-known technique, such as covering the periphery of the area where the bonding material 150 is formed with a so-called masking tape 280 (see FIG. 6(c-2) described later), and then the bonding material 150 is applied. In the illustrated example, the length in the transfer direction is 4 mm. To explain further, the length of the bonding material base 151 in the transfer direction is 3 mm, and the length of the narrow bonding material part 153 in the transfer direction is 1 mm.

[0045] <Mask 180> FIG. 5 is a schematic configuration diagram of the mask 180. The mask 180 is, for example, a metal member in the shape of a flat plate with a thickness of 0.3 mm. A wick-shaped opening 190, which is a through-hole, is formed in the mask 180. The wick-shaped opening 190 has a wick base region 191, which is the region for forming the wick base 131, and a wick claw region 193, which is the region for forming the wick claw 133. Here, the wick base region 191 is a substantially rectangular portion whose longitudinal direction is along the width direction. The wick claw region 193 is a portion that protrudes downstream in the transfer direction from the wick base region 191.

[0046] The mask 180 is arranged in alignment with the first side plate 111 in which the first recess 110 is formed. Then, a metal paste containing pure copper powder is guided into the wick-shaped opening 190 from above the mask 180, and the excess metal paste is scraped off using a rubber blade (so-called squeegee) or the like and applied. As a result, the material of the wick 130 is disposed in the first recess 110 with a predetermined thickness (for example, 0.3 mm). By solidifying the applied material of the wick 130 by sintering or the like, the wick 130 is formed in the first recess 110. Note that by using the mask 180, the process of forming the wick 130 including, for example, the wick claw 133 can be simplified.

[0047] <Manufacturing Process of Loop Heat Pipe 100> Figures 6 and 7 are diagrams showing the manufacturing process of loop heat pipe 100. Next, with reference to Figures 6 and 7, the manufacturing process of loop heat pipe 100 in the present embodiment will be described. Although illustration is omitted, it is assumed that masking has been preliminarily performed on the first side plate 111 except for the region where the first recess 110 is formed and the regions where the above-mentioned through-etching is performed (around the outer shape and the first through-hole 1129). Similarly, it is assumed that masking has been preliminarily performed on the second side plate 121 except for the region where the second recess 120 is formed and the regions where the above-mentioned through-etching is performed (around the outer shape and the second through-hole 1229).

[0048] First, as shown in Figure 6(a), the first side plate 111 and the second side plate 121 are placed on the support base TB. Then, as shown in Figure 6(b), etching is performed on the first side plate 111 and the second side plate 121 to form the first recess 110 and the second recess 120. Then, as shown in Figure 6(c), a metal paste is applied to the first recess 110 and the second recess 120. Specifically, as shown in Figure 6(c-1), a mask 180 is disposed on the first bottom surface 114 of the first recess 110, and the first metal paste 149 that becomes the wick 130 is applied. Also, as shown in Figure 6(c-2), a masking tape 280 is disposed on the second bottom surface 124 of the second recess 120, and the second metal paste 159 that becomes the bonding material 150 is applied.

[0049] Next, as shown in Figure 7(d), the first metal paste 149 and the second metal paste 159 are heated under their respective conditions (details will be described later). At this time, as shown in Figure 7(d-1), the first metal paste 149 is sintered to form the wick 130. This wick 130 is formed fixed to the first bottom surface 114. Similarly, as shown in Figure 7(d-2), the second metal paste 159 is sintered to form the bonding material 150. This bonding material 150 is formed fixed to the second bottom surface 124.

[0050] Next, as shown in FIG. 7(e), solder is placed around the first recess 110 and the second recess 120 of the first side plate 111 and the second side plate 121. In other words, solder is placed on the convex portions of the first side plate 111 and the second side plate 121. Note that the amount of solder placed on the convex portions is set to an amount that does not flow into the first recess 110 and the second recess 120 during melting. Also, the position of the solder placed on the convex portions is set to a position that does not flow into the first recess 110 and the second recess 120 during melting of the solder. Then, the first side plate 111 and the second side plate 121 on which the solder is placed are overlapped. At this time, the wick 130 and the bonding material 150 face each other and are arranged to abut against each other. Then, the first side plate 111 and the second side plate 121 may be pressed (see arrow F1 in the figure) to adjust (or decrease) the thickness of the wick 130.

[0051] Next, as shown in FIG. 7(f), by heating the first side plate 111 and the second side plate 121, the wick 130 and the bonding material 150 are joined. Then, after taking out of the furnace, a process for improving the airtightness is performed. For example, the airtightness can be made more reliable by well-known techniques such as placing solder on the side surfaces (for example, with a thickness of 0.3 mm) of the first side plate 111 and the second side plate 121, or applying and curing a sealing material such as a silicone-based or ultraviolet curable resin.

[0052] Note that in the illustrated example, as shown in FIG. 7(d), when sintering the first metal paste 149 and the second metal paste 159, the first side plate 111 and the second side plate 121 are heated while being supported by a support base TB having a flat surface. As a result, deformation of the first side plate 111 and the second side plate 121 due to heating can be suppressed as compared with the case where the first side plate 111 and the second side plate 121 are not supported by the support base TB.

[0053] <The first metal paste 149 and the second metal paste 159> The first metal paste 149 and the second metal paste 159 are formed as follows, for example. The first metal paste 149 serving as the wick 130 can be formed by mixing pure copper powder with a particle size of 45 μm or less in a binder solution. Also, the second metal paste 159 serving as the bonding material 150 can be formed by mixing 50 wt.% tin bronze powder with a particle size of 45 μm or less in a binder solution. The binder solution consists of a binder component and an organic solvent. The binder component can be selected from acrylic, butyral, cellulose, etc. The organic solvent can be selected from acetone, benzene, isopropanol, methanol, ethanol, toluene, n-butanol, xylene, ethylene glycol, ethyl acetate, terpineol, butyl acetate, tetrahydrofuran (THF), carbon tetrachloride, methyl ethyl ketone (MEK), chloroform, methyl isobutyl ketone (MIBK), n-hexane, methanol, cyclohexane, etc., but is not limited thereto.

[0054] The first metal paste 149 and the second metal paste 159 are subjected to debinding and sintering in a mesh belt type sintering furnace. Here, the first metal paste 149 and the second metal paste 159 disposed (coated) on the first side plate 111 and the second side plate 121 are sintered under the following conditions, for example. The first metal paste 149 has a debinding temperature of 600°C, a sintering temperature of 920°C, a holding time of 30 minutes, and an atmosphere gas of 80% nitrogen and 20% hydrogen. Also, the second metal paste 159 has a debinding temperature of 600°C, a sintering temperature of 600°C, a holding time of 30 minutes, and an atmosphere gas of 80% nitrogen and 20% hydrogen.

[0055] <Fixing of the first side plate 111 and the second side plate 121> As shown in Fig. 7(e), the fixing of the first side plate 111 and the second side plate 121 is performed under the following conditions, for example. First, a flux that activates the solder is applied to the first side plate 111, solder (for example, lead solder, 60% tin, 40% lead) is placed thereon, and a flux is applied on the solder. Then, with the first side plate 111 and the second side plate 121 overlapped, the portion where the wick 130 and the bonding material 150 are formed is pressed from the outside (see arrow F1 in the figure), and the combined thickness of the wick 130 and the bonding material 150 is adjusted to be equal to the flow path height.

[0056] Next, the first side plate 111 and the second side plate 121 are fixed (temporarily fixed) by spot welding or the like. Then, soldering and the bonding of the wick 130 and the bonding material 150 are performed in a mesh belt type sintering furnace. This bonding is carried out under the following heat treatment conditions, for example. That is, the temperature is 660 °C, the holding time is 30 minutes, and the atmosphere gas is 80% nitrogen and 20% hydrogen. Also, the first side plate 111 and the second side plate 121 are sandwiched between ceramic plates, a weight is placed, and heat treatment is performed with a load of 1 kg.

[0057] In addition, a leak test of the loop type heat pipe 100 formed under the above conditions was performed, and it was confirmed that there was no problem with degassing. Also, a heat load test of the manufactured loop type heat pipe 100 was performed, and operation at 4.5 W to 10 W was confirmed.

[0058] <Bonding by the bonding material 150> As described above, the wick 130 and the second side plate 121 are fixed to each other via the bonding material 150. The fixing by this bonding material 150 will be described. First, as shown in FIG. 7(f), the wick 130 formed by sintering the first metal paste 149 is in a state where the first surface side in the thickness direction is joined to the first side plate 111. Also, the second surface side in the thickness direction is required to be joined (sealed) to the second side plate 121. Here, unlike this embodiment, when joining the wick 130 to the second side plate 121 using solder (for example, 500°C) instead of the joining material 150, the solder may be absorbed by the wick 130, which can reduce the function of the wick 130. Also, unlike this embodiment, when joining the wick 130 to the second side plate 121 using brazing (for example, 800°C) or diffusion bonding (for example, 1000°C), the flow path of the working fluid may be blocked due to deformation such as deflection of the first side plate 111 and the second side plate 121.

[0059] Therefore, in the illustrated example, joining is performed using the joining material 150. As the material of this joining material 150, a material having a melting point lower than that of the material of the wick 130 (for example, pure copper), such as bronze, is used. The material of this joining material 150 is not particularly limited as long as it is likely to alloy or be compatible with the wick 130 and the second side plate 121. For example, when the wick 130 is formed of pure copper, other materials such as brass may be used as the joining material 150. Note that the material of the joining material 150 can be regarded as a material having the same composition (for example, copper) as the wick 130 and the second side plate 121. Also, the material of the joining material 150 can be regarded as a material having a melting point lower than that of the alloy of the second side plate 121. In the above example, the sintering of the first metal paste 149, that is, the first heating temperature is 920°C. Also, the joining of the wick 130 and the joining material 150, that is, the second heating temperature is 660°C, which is lower than the first time. This reduces the structural change of the wick 130 accompanying the second heating.

[0060] In this way, by joining the wick 130 and the joining material 150, the wick 130 is fixed to the first side plate 111 and the second side plate 121. The fixed wick 130 and joining material 150 function as a pressure partition between the vapor space 140 and the liquid reservoir 160.

[0061] <First Modification Example> FIG. 8 is a diagram showing the first modification example. The first modification example will be described with reference to FIG. 8. In the following description, the same parts as those in the configuration of the above-described embodiment may be denoted by the same reference numerals, and detailed descriptions thereof may be omitted.

[0062] In the above-described embodiment, it has been described that the wick 130 is generally comb-shaped, but it is not limited thereto as long as it can be installed in the same plane. For example, as shown in FIG. 8(a), a wick 230 may be formed. The wick 230 has a wick base portion 231 whose longitudinal direction is along the width direction, a plurality of wick claw portions 233 protruding from the wick base portion 231 toward the downstream side in the transfer direction, and a wick convex portion 237 which is a portion protruding from the wick base portion 231 toward the upstream side in the transfer direction. This wick 230 is formed by applying a material to be the wick 230, similarly to the above-described embodiment.

[0063] Here, when there is little working fluid stored in the liquid reservoir portion 160, the working fluid may be unevenly distributed in the liquid reservoir portion 160. Due to this unevenness of the working fluid, it becomes difficult to supply the working fluid to the wick 230, and there is a possibility that the operating performance of the wick 230 may deteriorate. Therefore, by forming the wick convex portion 237 protruding toward the liquid reservoir portion 160 like the wick 230, even when the working fluid is unevenly distributed in the liquid reservoir portion 160, the working fluid can be stably supplied to the wick base portion 231 and the wick claw portions 233 via the wick convex portion 237.

[0064] Note that the wick convex portion 237 can be regarded as another wick, that is, a secondary wick for supplying the working fluid to the wick base portion 231 and the like. Further, as long as the wick convex portion 237 has a structure in which a predetermined capillary force acts, the material, shape (for example, pillar structure or mesh structure), etc. are not particularly limited. Note that the dimensions of the wick convex portion 237 may be determined so that the flow pressure loss does not become larger than a predetermined value.

[0065] Also, as shown in FIG. 8(b), both ends of the wick convex portion 237 in the thickness direction are joined to the first bottom surface 114 of the first side plate 111 and the second bottom surface 124 of the second side plate 121, respectively. Thereby, deformation of the first side plate 111 and the second side plate 121 can be suppressed. Additionally, for example, even in a configuration where the thicknesses of the first side plate 111 and the second side plate 121 are thin, expansion and depression (dents) of the first side plate 111 and the second side plate 121 can be suppressed by the wick convex portion 237.

[0066] Note that, as a configuration for suppressing deformation of the first side plate 111 and the second side plate 121, as shown in FIG. 8(c), a wick 330 may be formed. The wick 330 has a wick base portion 331 whose longitudinal direction is along the width direction, a plurality of wick claw portions 333 protruding from the wick base portion 331 to the downstream side in the transfer direction, and a plurality of wick separation portions 337 spaced apart from the wick base portion 331 and the wick claw portions 333. This wick 330 is formed by applying a material to be the wick 330 in the same manner as in the above-described embodiment. Note that part or all of the wick separation portions 337 can be formed in the etching process of forming the first recess 110 and the second recess 120 as described above.

[0067] Here, in the illustrated example, a plurality of wick separation portions 337 are formed in the liquid reservoir portion 160. Both ends of this wick separation portion 337 in the thickness direction are joined to the first bottom surface 114 of the first side plate 111 and the second bottom surface 124 of the second side plate 121, and deformation of the first side plate 111 and the second side plate 121 can be suppressed.

[0068] Note that, as shown in the figure, the wick separation portion 337 is not limited to being disposed within the liquid reservoir portion 160, and may be provided in the vapor space 140 in addition to or instead of the liquid reservoir portion 160. Also, the wick separation portion 337 may be provided in the vapor pipe 105, the condenser 107, the liquid pipe 109, etc.

[0069] This wick separation part 337 has a function of preventing blockage or narrowing of the flow path due to negative pressure. This wick separation part 337 is provided with dimensions and intervals that do not impede the flow of the working fluid. Also, by using the same material as the wick base part 331 and the wick claw part 333 and forming them through the same process for the wick separation part 337, the manufacturing process can be simplified. Note that the wick base part 331 and the wick claw part 333 may be formed of different materials from each other.

[0070] Now, as shown in FIG. 8(d), a wick 430 may be disposed in the liquid reservoir part 160. This wick 430 includes a wick base part 431 whose longitudinal direction is along the width direction, and a plurality of wick claw parts 433 that protrude from the wick base part 431 toward the downstream side in the transfer direction. And the wick base part 431 and the wick claw parts 433 are disposed in the liquid reservoir part 160. As a result, the wick 430 can receive the supply of the liquid-phase working fluid from three side surfaces, namely, the wick upstream-side end surface 437, the wick first side surface 438, and the wick second side surface 439. Additionally, even when the working fluid is unevenly distributed within the liquid reservoir part 160, the wick 430 can stably receive the supply of the working fluid.

[0071] Here, a bonding material 450 is disposed on the wick 430 in an overlapping manner. The bonding material 450 has a substantially U-shaped configuration. To further explain, the bonding material 450 includes an upstream part 451 that is a part along the wick upstream-side end surface 437, a first part 453 that is a part along the wick first side surface 438, and a second part 455 that is a part along the wick second side surface 439. Due to this upstream part 451, the first part 453, and the second part 455, leakage of the working fluid in the region where the wick 430 is in contact with the liquid reservoir part 160 is suppressed.

[0072] <Second Modified Example> FIG. 9 is a diagram showing a second modified example. While referring to FIG. 9, the second modified example will be described. In the above-described embodiment, it has been described that the general shape of the wick 130 is comb-shaped, but it is not limited to this.

[0073] For example, as shown in FIG. 9(a), a wick 1130 may be formed. The wick 1130 includes a wick base portion 1131 whose longitudinal direction is along the width direction, and a plurality of wick claw portions 1133 protruding from the wick base portion 1131 to the downstream side in the transfer direction. Each of the wick claw portions 1133 has a different length in the width direction according to the position in the transfer direction. Specifically, the wick claw portion 1133 becomes smaller in dimension in the width direction as it advances to the downstream side in the transfer direction. Also, the slit 1135, which is the gap between the wick claw portions 1133, becomes larger in dimension in the width direction as it advances to the downstream side in the transfer direction.

[0074] Also, as shown in FIG. 9(b), a wick 1230 may be formed. The wick 1230 includes a wick base portion 1231 whose longitudinal direction is along the width direction, and a plurality of wick claw portions 1233 protruding from the wick base portion 1231 to the downstream side in the transfer direction. This wick claw portion 1233 is a portion that curves in a substantially S shape, in other words, a portion formed in a wave shape. As a result, the slit 1235 is also formed to be curved.

[0075] Also, as shown in FIG. 9(c), a wick 1330 may be formed. The wick 1330 is configured to be spaced apart from each other in the transfer direction and connected at the central portion in the width direction. To explain further, the wick 1330 has a plurality of wick base portions 1331, 1333, 1335 whose longitudinal direction is along the width direction, and a connecting portion 1337 that connects the wick base portions 1331, 1333, 1335 at the central portion in the width direction. The gaps 1336, 1338 formed between the wick base portions 1331, 1333, 1335 function as flow paths for the working fluid.

[0076] Also, as shown in FIG. 9(d), a wick 1430 may be formed. The wick 1430 includes a wick base portion 1431 whose longitudinal direction is along the width direction, and a plurality of wick claw portions 1433 protruding from the wick base portion 1431 to the downstream side in the transfer direction. Here, the wick claw portion 1433 includes a wide portion 1437 protruding in the width direction from the central portion in the transfer direction of the wick claw portion 1433. The gap 1435 between the wick claw portions 1433 functions as a flow path for the working fluid.

[0077] Also, as shown in FIG. 9(e), a wick 1530 may be formed. The wick 1530 includes a wick base portion 1531 whose longitudinal direction is along the width direction, two wick claw portions 1533 protruding from both ends in the width direction of the wick base portion 1531 to the downstream side in the transfer direction, and a protruding portion 1535 protruding from the wick base portion 1531 to the downstream side in the transfer direction. Here, the protruding portion 1535 includes a wide portion 1537 having a large dimension in the width direction on the downstream side in the transfer direction. In the illustrated example, the wide portion 1537 is substantially circular in plan view. The gap 1536 between the wick claw portion 1533 and the spaced portion 1535 functions as a flow path for the working fluid.

[0078] <Third Modification> FIG. 10 is a diagram showing a third modification. The third modification will be described with reference to FIG. 10. In the above embodiment, it has been described that the wick 130 is formed by coating. Here, when the wick 130 is formed by coating, the shape of the wick 130 can be easily changed, for example, by changing the thickness of the mask 180. Further explained, by changing the shape of the mask 180 or the like and switching the coating mode of the wick 130, the configuration of the wick 130 can be changed. As a result, in the design stage of the wick 130, it becomes easy to design the wick 130 according to the performance required for the wick 130.

[0079] For example, as shown in FIG. 10(a), the mask 2180 may be configured such that its thickness changes according to its position in the transfer direction. More specifically, the mask 2180 is configured such that the thickness of the region 2181 where the wick-shaped opening 2190 is formed in the transfer direction decreases as it moves downstream.

[0080] By using the mask 2180, a wick 2130 as shown in FIG. 10(b) is formed. The dimension of the wick 2130 in the thickness direction changes according to its position in the transfer direction. Specifically, the wick 2130 is configured such that its thickness decreases as it moves downstream in the transfer direction.

[0081] Also, as shown in FIG. 10(c), a wick 2230 may be formed. The material constituting the wick 2230 changes according to its position in the transfer direction. More specifically, the wick 2230 is configured such that its average opening diameter decreases as it moves downstream in the transfer direction. Additionally, the wick 2230 has a first portion 2231 with a first average opening diameter and a second portion 2233 with a second average opening diameter that is different from (smaller than) the first average opening diameter.

[0082] The dimension of the wick 2230 in the thickness direction is constant, but the thickness of the first portion 2231 decreases as it moves downstream in the transfer direction, and the thickness of the second portion 2233 increases as it moves downstream in the transfer direction. Also, as the material for the first portion 2231 and the material for the second portion 2233, materials that are different from each other, such as having different particle sizes, may be used. Then, after applying the material for the first portion 2231, the material for the second portion 2233 is applied and sintered on top of the first portion 2231 to form the wick 2230.

[0083] Also, as shown in FIG. 10(d), a wick 2330 may be formed. The configuration of the wick 2330 changes according to its position in the transfer direction. Specifically, the wick 2330 is configured such that the average opening diameter of the downstream side in the transfer direction is smaller than that of the upstream side in the transfer direction. In the illustrated example, the wick 2330 reduces the average opening diameter by pressurizing a part of the applied material without using a plurality of materials. Specifically, after applying the material 2332 to be the wick 2330 with a certain thickness, only the downstream side 2333 in the transfer direction is pressurized (see F3). As a result, the average opening diameter of the downstream side 2333 in the transfer direction becomes smaller compared to the upstream side 2331 in the transfer direction. Also, the thickness of the downstream side 2333 in the transfer direction becomes smaller compared to the upstream side 2331 in the transfer direction.

[0084] Also, as shown in FIG. 10(e), a wick 2430 may be formed. Specifically, after applying the material 2431 to be the wick 2430 while inclining it to become thicker (higher) as it progresses downstream in the transfer direction, it is pressurized to make the thickness uniform (see F4). As a result, the average opening diameter of the downstream side 2437 in the transfer direction becomes smaller compared to the upstream side 2435 in the transfer direction. That is, the configuration is such that the average opening diameter decreases (inclines) as it progresses downstream in the transfer direction. Also, in the illustrated example, the thickness of the upstream side 2435 and the downstream side 2437 in the transfer direction is the same.

[0085] <Electronic device> FIG. 11 is a diagram showing an apparatus including a loop heat pipe 100. Next, an apparatus including the loop heat pipe 100 will be described with reference to FIG. 11.

[0086] As shown in FIG. 11(a), the loop heat pipe 100 is provided in an electronic device such as a mobile phone 800. The illustrated mobile phone 800 is a so-called smartphone. This mobile phone 800 includes a central processing unit (CPU) 801 which is an example of a heating element, and a loop heat pipe 100 for cooling the CPU 801. Then, the heat generated by the CPU 801 is controlled by the loop heat pipe 100.

[0087] Here, as described above, the loop heat pipe 100 does not require external power supply. That is, it can operate without power. In addition, the loop heat pipe 100 can enable long-distance heat transport (for example, 100 mm to 1 m, etc.) and high-efficiency heat transport by using latent heat. Also, the loop heat pipe 100 is thin in thickness and excellent in layout property.

[0088] In recent years, due to the introduction of the so-called fifth-generation mobile communication system (5G), etc., the requirements for high-frequency communication (3.7, 4.5, 28 GHz) have been increasing. And in smartphones and tablet terminals such as the mobile phone 800, for example, densification by adding components, improvement of the required values of the processing capabilities of the CPU and GPU, increase in heat generation density, increase in heat transport, etc. are required. The loop heat pipe 100 described above is a device that can satisfy these required performances.

[0089] Here, as an example of an electronic device, the mobile phone 800 has been used for the explanation, but the above loop heat pipe 100 may be provided in a personal computer, a tablet-type terminal, a projector, etc. Also, the loop heat pipe 100 can be provided in various devices such as an Electronic Control Unit (ECU) and a battery mounted on an automobile, or a satellite.

[0090] Here, as shown in FIG. 11(b), the loop heat pipe 100 may be provided on a card 900. Note that the card 900 is called a so-called smart card, and its specifications are defined by an international standard (ISO / IEC7810).

[0091] Smart cards are mainly classified into contact type and non-contact type. Inside the card, devices with a thickness of 0.4 mm or less, such as IC chips, short-range wireless communication antennas (NFC), Bluetooth (registered trademark) communication, fingerprint authentication sensors, displays, power supply ICs, DC / DC converters, batteries, capacitors, etc., are incorporated as required. In the future, with the improvement of the performance of IC chips and each device, the smart card is expected to be PC-like. The driving power for the PC is received through the card reader 950 in the case of contact type and through the NFC antenna in the case of non-contact. And since the heat generation amount of the PC CPU 901 increases as the computing speed improves, it is necessary to provide a cooling mechanism inside the card 900.

[0092] The loop heat pipe 100 can be incorporated into the card 900 because, for example, its thickness is 0.3 mm. Also, the loop heat pipe 100 may exhaust heat by exposing a part of the surface (such as the condensation surface) of the condenser 107 to the outside of the card 900. To explain further, in the design where the card 900 is contact type and the PC CPU 901 has to be placed inside the card reader 950, the loop heat pipe 100 can be effective.

[0093] <Other Variants> Figure 12 is a diagram showing a variant of the loop heat pipe 1100. In the above description, it was explained that the heat generated in the heat source 10 is released at the condenser 107 of the loop heat pipe 100 through the working fluid. Here, the loop heat pipe 100 may be configured to release the heat of the condenser 107 more efficiently. For example, like the loop heat pipe 1100 shown in Figure 12, it may be configured to have a fin structure 1101 that expands the heat transfer area and dissipate heat through the fin structure 1101.

[0094] Also, in the above description, it has been described that the wick 130 is applied while using the mask 180, but it is not limited to this. For example, instead of the mask 180, well-known techniques such as a screen used for screen printing, a dispenser, or a masking tape 280 may be used to apply the wick 130 to a predetermined area. Further, after forming a sheet-like (thin plate-like) wick material by a coater, the wick 130 may be formed by cutting it into a predetermined shape.

[0095] Also, although it has been described that the wick 130 is formed by application, the formation method of the wick 130 is not limited to this. For example, the material of the wick 130 may be arranged on the first side plate 111 in a powder state and sintered to form the wick 130. For example, the powder material may be spread with a thickness of about 0.1 mm at the position where the wick 130 is formed on the first side plate 111. In addition, as in the above embodiment, by making a paste by combining the powder material and the binder, it may be possible to thinly and uniformly apply the material of the wick 130.

[0096] Also, the material that becomes the wick 130 is not limited to the above-described metal porous body. Other materials such as a ceramic porous body, a glass porous body, and porous fibers may be used as long as they can be processed into powder and their positions can be fixed to each other by heating.

[0097] Also, in the above description, it has been described that the first recess 110 and the second recess 120 are formed by etching, but it is not limited thereto. For example, the first recess 110 and the second recess 120 may be formed by performing well-known processes such as cutting or pressing on the first side plate 111 and the second side plate 121. Further, if it is possible to form a space for arranging the wick 130 and the bonding material 150 between the first side plate 111 and the second side plate 121, a configuration in which either one of the first recess 110 and the second recess 120 is formed may be used. Note that by forming the first recess 110 by etching as described above, the first bottom surface 114 can be roughened, and the wick 130 can be more reliably fixed to the first side plate 111. Also, by forming the second recess 120 by etching, the second bottom surface 124 can be roughened, and the bonding material 150 can be more reliably fixed to the second side plate 121.

[0098] Also, the first side plate 111 and the second side plate 121 are not limited to those having a generally plate-like shape as long as the configuration can suppress the dimensions in the thickness direction. For example, the first side plate 111 and the second side plate 121 may have a configuration in which irregularities are formed on the plate surface or a configuration in which other members are fixed to the plate surface. Additionally, the first side plate 111 and the second side plate 121 can be regarded as a main body and a lid body covering the main body, respectively. Further, the loop type heat pipe 100 may be formed by sandwiching a frame body separate from the first side plate 111 and the second side plate 121 between the first side plate 111 and the second side plate 121.

[0099] Also, in the above description, it has been described that the bonding material 150 is formed by applying the material of the bonding material 150 and then sintering it, but it is not limited thereto. For example, the bonding material 150 may be formed in advance as a plate-like member, and may be fixed to the second side plate 121 and the wick 130 by heating in a state where the plate-like bonding material 150 is sandwiched between the second side plate 121 and the wick 130.

[0100] Also, in the above description, the joining of the first side plate 111 and the second side plate 121 was described as being performed by soldering, but it is not limited to this. For example, if the inflow of the brazing material into the first recess 110 and the second recess 120 can be suppressed, the first side plate 111 and the second side plate 121 may be joined by brazing. Also, if the flow path can be prevented from being blocked, such as by forming pillars in the flow path, diffusion bonding may be used. Further, joining may be performed by adhesion with an adhesive, laser bonding, ultrasonic bonding, friction stir bonding, or the like.

[0101] Also, in the above description, the loop heat pipe 100 was described as a heat exchanger, but it is not particularly limited as long as it is a two-phase heat transport device. For example, in other heat exchangers such as a vapor chamber, the above configuration such as the wick 130 and the first side plate 111 may be adopted.

[0102] Now, although various embodiments and modifications have been described above, it is of course possible to configure them by combining these embodiments and modifications with each other. Also, the present disclosure is not limited to the above embodiments at all, and can be implemented in various forms without departing from the gist of the present disclosure.

[0103] The loop heat pipe 100 is an example of a heat exchanger. The first side plate 111 is an example of a first plate member. The first recess 110 is an example of a recess. The first metal paste 149 is an example of a material containing powder. The wick 130 is an example of an evaporator. The second side plate 121 is an example of a second plate member. The wick-type opening 190 is an example of a hole. The mask 180 is an example of a covering member. The wick base 1131 is an example of a substrate. The wick claw portion 1133 is an example of a lower fluid. The first portion 2231 is an example of a first material. The second portion 2233 is an example of a second material. The wick separation portion 337 is an example of a sintered body. The mobile phone 800 is an example of a device. The heating element 10 is an example of a heat generating component.

Description of Reference Numerals

[0104] 100…Loop heat pipe, 111…First side plate, 121…Second side plate, 130…Wick, 150…Bonding material, 149…First metal paste, 180…Mask

Claims

1. A manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a liquid-phase working fluid into a gas phase while moving the liquid-phase working fluid by capillary force, a step of forming a recess on the plate surface of a first plate member that is a plate-shaped member; a step of applying a material containing powder to a predetermined region in the recess; a step of hardening the material applied to the predetermined region to form the evaporator; a step of covering the recess provided with the evaporator with a second plate member that is a plate-shaped member, and fixing the first plate member and the second plate member; including, The heat exchanger is provided between the second plate member and the evaporator, and includes a joint portion that joins the second plate member and the evaporator so as to suppress the flow of a liquid-phase fluid. Manufacturing method.

2. a step of disposing a covering member provided with holes for passing the material in the shape of the predetermined region on the surface covering the first plate member on the first plate member; a step of applying the material through the holes of the covering member; The manufacturing method according to claim 1, including.

3. The evaporator has a base body extending in a direction intersecting the direction in which the liquid-phase working fluid in the evaporator moves, and a plurality of lower fluid bodies located on the downstream side in the moving direction from the base body, The holes are in a shape corresponding to the base body and the plurality of lower fluid bodies. The manufacturing method according to claim 2.

4. The covering member has different thicknesses according to the position in the direction in which the liquid-phase working fluid in the evaporator moves. The manufacturing method according to claim 2 or 3.

5. The material applied to the predetermined region is in contact with the inner side surface of the recess at both ends in a direction intersecting the direction in which the liquid-phase working fluid moves in the evaporator. The manufacturing method according to any one of claims 1 to 4.

6. In the step of applying the material, the applied material becomes thinner as it progresses to the downstream side in the direction in which the liquid-phase working fluid in the evaporator moves. The manufacturing method according to any one of claims 1 to 5.

7. The step of pressing a part of the region of the material applied to the predetermined region The manufacturing method according to any one of claims 1 to 6, including this step.

8. The step of forming the concave portion forms the concave portion by etching the plate surface of the first plate member. The manufacturing method according to any one of claims 1 to 7.

9. A manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a liquid-phase working fluid into a gas phase while moving the liquid-phase working fluid by capillary force, The step of forming a concave portion on the plate surface of a first plate member that is a plate-shaped member; The step of applying a material containing powder to a predetermined region in the concave portion; The step of solidifying the material applied to the predetermined region to form the evaporator; The step of covering the concave portion provided with the evaporator with a second plate member that is a plate-shaped member and fixing the first plate member and the second plate member; including The material applied to the predetermined region contacts the inner side surface of the concave portion at both ends in a direction intersecting the direction in which the liquid-phase working fluid moves within the evaporator. The material applied to the predetermined region is separated from the inner side surface of the concave portion on the upstream side in the moving direction compared to the portion that contacts the inner side surface of the concave portion. Manufacturing method.

10. A manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates a liquid-phase working fluid into a gas phase while moving the liquid-phase working fluid by capillary force, A step of forming a recess on the plate surface of the first plate member which is a plate-shaped member, A step of applying a material containing powder to a predetermined region in the recess, A step of hardening the material applied to the predetermined region to form the evaporator, A step of covering the recess provided with the evaporator with a second plate member which is a plate-shaped member, and fixing the first plate member and the second plate member, comprising, The step of applying the material includes a first application step of applying a first material and a second application step of applying a second material on top of the first material, The thicknesses of the first material and the second material are different according to the position in the direction in which the working fluid in the liquid phase in the evaporator moves. Manufacturing method. A manufacturing method for manufacturing a heat exchanger having an evaporator that absorbs heat from the outside and evaporates the working fluid in the liquid phase into the gas phase while moving it by capillary force, A step of forming a recess on the plate surface of the first plate member which is a plate-shaped member, A step of applying a material containing powder to a predetermined region in the recess, A step of hardening the material applied to the predetermined region to form the evaporator, A step of covering the recess provided with the evaporator with a second plate member which is a plate-shaped member, and fixing the first plate member and the second plate member, A step of applying the material to other positions in the flow path of the working fluid other than the predetermined region, comprising, In the step of forming the evaporator, the material applied to the other position is sintered to form a sintered body, The sintered body is sandwiched between the first plate member and the second plate member at the other position. Manufacturing method.

12. A manufacturing method for manufacturing an apparatus provided with a heat-generating component and a heat exchanger having an evaporator that absorbs heat from the heat-generating component and evaporates it into a gas phase while moving a liquid-phase working fluid by capillary force, forming a recess on the plate surface of a first plate member that is a plate-shaped member; applying a material containing powder to a predetermined region in the recess; hardening the material applied to the predetermined region to form the evaporator; covering the recess provided with the evaporator with a second plate member that is a plate-shaped member, and fixing the first plate member and the second plate member; fixing the heat-generating component to at least one of the first plate member and the second plate member; comprising, the heat exchanger is provided between the second plate member and the evaporator, and includes a joint portion that joins the second plate member and the evaporator so as to suppress the flow of a liquid-phase fluid. Manufacturing method.

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