LOOP-TYPE HEAT PIPE

A loop-type heat pipe includes a loop-type heat pipe main body including a loop-shaped flow path in which a working fluid is enclosed, a first magnet provided to the loop-type heat pipe main body, a heat dissipation plate thermally connected to the loop-type heat pipe main body, and a second magnet provided to the heat dissipation plate and provided to face the first magnet. The first magnet and the second magnet are provided so that different magnetic poles face to each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Patent Application No. 2022-007090 filed on Jan. 20, 2022, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a loop-type heat pipe.

BACKGROUND ART

In the related art, as a device configured to cool a heat-generating component of a semiconductor device (for example, a CPU or the like) mounted on an electronic device, suggested is a heat pipe configured to transport heat by using a phase change of a working fluid (for example, refer to Patent Literatures 1 and 2).

As an example of the heat pipe, known is a loop-type heat pipe including an evaporator configured to vaporize a working fluid by heat of a heat-generating component and a condenser configured to cool and condense the vaporized working fluid, in which the evaporator and the condenser are connected to each other by a liquid pipe and a vapor pipe configured to form a loop-shaped flow path. In the loop-type heat pipe, the working fluid flows in one direction along the loop-shaped flow path.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

In the meantime, in the above-described loop-type heat pipe, improvement in heat dissipation property is desired, and there is still room for improvement in this respect.

Certain embodiment provides a loop-type heat pipe.

The loop-type heat pipe comprises

a loop-type heat pipe main body including a loop-shaped flow path in which a working fluid is enclosed;

a first magnet provided to the loop-type heat pipe main body;

a heat dissipation plate thermally connected to the loop-type heat pipe main body; and

a second magnet provided to the heat dissipation plate and provided to face the first magnet.

The first magnet and the second magnet are provided so that different magnetic poles face to each other.

According to one aspect of the present invention, it is possible to obtain an effect capable of improving a heat dissipation property.

DESCRIPTION OF EMBODIMENTS

Hereinafter, one embodiment will be described with reference to the accompanying drawings.

Note that, for convenience sake, in the accompanying drawings, a characteristic part may be enlarged so as to easily understand the feature, and the dimension ratios of the respective constitutional elements may be different in the respective drawings. In addition, in the cross-sectional views, hatching of some members is shown in a satin form and hatching of some members is omitted, so as to easily understand a sectional structure of each member. In the respective drawings, an X-axis, a Y-axis, and a Z-axis orthogonal to each other are shown. In descriptions below, for convenience sake, a direction extending along the X-axis is referred to as ‘X-axis direction’, a direction extending along the Y-axis is referred to as ‘Y-axis direction’, and a direction extending along the Z-axis is referred to as ‘Z-axis direction’. Note that, in the present specification, ‘in a top view’ means seeing a target object in the Z-axis direction, and ‘planar shape’ means a shape of a target object as seen in the Z-axis direction.

(Overall Configuration of Loop-Type Heat Pipe LH1)

A loop-type heat pipe LH1shown inFIG.1is accommodated in a mobile electronic device M1such as a smart phone and a tablet terminal. The loop-type heat pipe LH1includes a loop-type heat pipe main body10, a heat dissipation plate30thermally connected to an outer surface of the loop-type heat pipe main body10, a first magnet50provided in the loop-type heat pipe main body10, and a second magnet60provided in the heat dissipation plate30.

As shown inFIGS.2and3, a heat-generating component100is thermally connected to the loop-type heat pipe LH1. As shown inFIG.3, the heat-generating component100is mounted on a wiring substrate101. The heat-generating component100and the wiring substrate101are accommodated in the electronic device M1. Here, the electronic device M1is, for example, an electronic device on which the heat-generating component100and a device configured to cool the heat-generating component100are mounted. As the device configured to cool the heat-generating component100, known is a heat pipe configured to transport heat by using a phase change of a working fluid. As an example of the heat pipe, the loop-type heat pipe LH1may be exemplified.

(Configuration of Loop-Type Heat Pipe Main Body10)

As shown inFIG.2, the loop-type heat pipe main body10includes an evaporator11, a vapor pipe12, a condenser13and a liquid pipe14.

The evaporator11and the condenser13are connected by the vapor pipe12and the liquid pipe14. The evaporator11has a function of vaporizing a working fluid C to generate vapor Cv. The vapor Cv generated in the evaporator11is sent to the condenser13via the vapor pipe12. The condenser13has a function of condensing the vapor Cv of the working fluid C. The condensed working fluid C is sent to the evaporator11via the liquid pipe14. The vapor pipe12and the liquid pipe14are configured to form a loop-shaped flow path15through which the working fluid C or the vapor Cv is caused to flow. In the flow path15, the working fluid C is enclosed.

The vapor pipe12is formed, for example, by an elongated pipe body. The liquid pipe14is formed, for example, by an elongated pipe body. In the present embodiment, the vapor pipe12and the liquid pipe14are the same in dimension (i.e., length) in a length direction, for example. Note that, the length of the vapor pipe12and the length of the liquid pipe14may be different from each other. For example, the length of the vapor pipe12may be shorter than the length of the liquid pipe14. Here, in the present specification, the ‘length direction’ of the evaporator11, the vapor pipe12, the condenser13and the liquid pipe14is a direction that coincides with a direction (refer to an arrow in the drawing) in which the working fluid C or vapor Cv flows in each member. In addition, in the present specification, the ‘same’ includes not only a case in which comparison targets are exactly the same but also a case in which there is a slight difference between the comparison targets due to influences of dimensional tolerances and the like,

As shown in FIG,3, the evaporator11is fixed in close contact with the heat-generating component100. The evaporator11is fixed to an upper surface of the heat-generating component100, for example. The evaporator11has, for example, a plurality of (four, in the present embodiment) attaching holes11X. Each attaching hole11X is formed to penetrate through the evaporator11in a thickness direction (here, Z-axis direction). The evaporator11is fixed to the wiring substrate101by, for example, a screw102inserted in each attaching hole11X and a nut103screwed onto the screw102. The heat-generating component100is mounted on the wiring substrate101. The heat-generating component100is mounted on the wiring substrate101by humps100A, for example. A lower surface of the evaporator11is in close contact with the upper surface of the heat-generating component100. As the heat-generating component100, for example, a semiconductor device such as a CPU (Central Processing Unit) chip or a GPU (Graphics Processing Unit) chip may be used.

As shown inFIG.2, the working fluid C in the evaporator11is vaporized by heat generated by the heat-generating component100, and the vapor Cv is accordingly generated. The vapor Cv generated in the evaporator11is guided to the condenser13via the vapor pipe12.

The vapor pipe12has a pair of pipe walls12wprovided on both sides in a width direction orthogonal to the length direction of the evaporator12, in a top view, and a flow path12rprovided between the pair of pipe walls12w, for example. The flow path12ris formed to communicate with an internal space of the evaporator11. The flow path12ris a part of the loop-shaped flow path15.

The condenser13has a heat dissipation plate13pwhose area is increased for heat dissipation, and a flow path13rprovided in the heat dissipation plate13p, for example. The flow path13rhas a flow path r1formed to communicate with the flow path12rand extending in the Y-axis direction, a flow path r2bent from the flow path r1and extending in the X-axis direction, and a flow path r3bent from the flow path r2and extending in the Y-axis direction. The flow path13r(flow paths r1to r3) is a part of the loop-shaped flow path15. The condenser13has pipe walls13wprovided on both sides in a direction orthogonal to a length direction of the flow path13r, i.e., the flow paths r1to r3, in the top view. The vapor Cv guided via the vapor pipe12is condensed in the condenser33. The working fluid C condensed in the condenser13is guided to the evaporator11through the liquid pipe14.

The liquid pipe14has a pair of pipe walls14wprovided on both sides in the width direction orthogonal to the length direction of the liquid pipe14, in the top view, and a flow path14rprovided between the pair of pipe walls14w, for example. The flow path14ris formed to communicate with the flow path13r(specifically, the flow path r3) of the condenser13and the internal space of the evaporator11. The flow path14ris a part of the loop-shaped flow path15.

In the loop-type heat pipe LH1, the heat generated by the heat-generating component100is transferred to the condenser13and dissipated in the condenser13. Thereby, the heat-generating component is100is cooled, so that the temperature rise of the heat-generating component100is suppressed.

Here, as the working fluid C, a fluid having a high vapor pressure and a high latent heat of vaporization is preferably used. By using such working fluid C, it is possible to effectively cool the heat-generating component100by the latent heat of vaporization. As the working fluid C, ammonia, water, freon, alcohol, acetone or the like can be used, for example.

(Specific Structure of Condenser13)

FIG.1shows a cross section of the loop-type heat pipe LH1taken along a line1-1ofFIG.2. This cross section is a plane orthogonal to the direction in which the working fluid flows in the condenser13and the liquid pipe14.

As shown inFIG.1, the condenser13has a structure in which three metal layers21,22and23, for example, are stacked. In other words, the condenser13has a structure in which the metal22, which is an inner metal layer, is stacked between the metal layers21and23, which are a pair of outer metal layers. The inner metal layer of the condenser13of the present embodiment is configured by only one metal layer22.

Each of the metal layers21to23is a copper (Cu) layer having excellent thermal conductivity. The plurality of metal layers21to23are directly bonded to each other by solid-phase bonding such as diffusion bonding, pressure welding, friction pressure welding and ultrasonic bonding. Note that, inFIG.1, the metal layers21to23are identified by solid lines for easy understanding. For example, when the metal layers21to23are integrated by diffusion bonding, interfaces of the respective metal layers21to23may be lost, and therefore, boundaries may not be clear, As used herein, the solid-phase bonding is a method of heating and softening bonding target objects in a solid-phase (solid) state without melting the same, and then further heating, plastically deforming and bonding the bonding target objects. Note that, the metal layers21to23are not limited to the copper layers and may also be formed of stainless steel, aluminum, magnesium alloy or the like. In addition, for some of the stacked metal layers21to23, a material different from the other metal layers may be used. A thickness of each of the metal layers21to23may be set to about 50 μm to 200 μm, for example. Note that, some of the metal layers21to23may be formed to have a thickness different from those of the other metal layers, and all the metal layers may be formed to have thicknesses different from each other.

The condenser13is configured by the metal layers21to23stacked in the Z-axis direction, and has the flow path13rand the pair of pipe walls13wprovided on both sides of the flow path13rin the Y-axis direction.

The metal layer22is stacked between the metal layer21and the metal layer23. An upper surface of the metal layer22is bonded to the metal layer21. A lower surface of the metal layer22is bonded to the metal layer23. The metal layer22has a through-hole22X penetrating through the metal layer22in the thickness direction, and a pair of pipe walls22wprovided on both sides of the through-hole22X in the Y-axis direction. The through-hole22X constitutes the flow path13r.

The metal layer21is stacked on the upper surface of the metal layer22. The metal layer21has pipe walls21wprovided at positions overlapping the pipe walls22win the top view, and an upper wall21uprovided at a position overlapping the flow path13rin the top view. A lower surface of the pipe wall21wis bonded to an upper surface of the pipe wall22w. The upper wall21uis provided between the pair of pipe walls21w. A lower surface of the upper wall21uis exposed to the flow path13r. In other words, the upper wall21uconstitutes the flow path13r.

The metal layer23is stacked on the lower surface of the metal layer22. The metal layer23has pipe walls23wprovided at positions overlapping the pipe walls22win the top view, and a lower wall23dprovided at a position overlapping the flow path13rin the top view. An upper surface of the pipe wall23wis bonded to a lower surface of the pipe wall22w. The lower wall23dis provided between the pair of pipe walls23w. An upper surface of the lower wall23dis exposed to the flow path13r. In other words, the lower wail23dconstitutes the flow path13r.

The flow path13ris configured by the through-hole22X of the metal layer22, The flow path13ris formed by a space surrounded by an inner wall surface of the through-hole22X, the lower surface of the upper wall21u, and the upper surface of the lower wall23d.

Each pipe wall13wis configured by, for example, the pipe wall21wof the metal layer21, the pipe wall22wof the metal layer22, and the pipe wall23wof the metal layer23. As shown inFIG.1, the condenser13has a first facing surface13A facing the heat dissipation plate30. The first facing surface13A is configured by, for example, the upper surface of the metal layer21in the condenser13. Note that, in the present specification, ‘facing’ indicates that surfaces or members are in front of each other, and includes not only a case in which they are completely in front of each other, but also a case in which they are partially in front of each other. Also, in the present specification, ‘facing’ includes both a case in which a member different from two parts is interposed between the two parts and a case in which no member is interposed between the two parts.

The vapor pipe12shown inFIG.2is formed by the three stacked metal layers21to23(refer to FIG,1), similarly to the condenser13. For example, in the vapor pipe12, the flow path12ris formed by forming a through-hole penetrating through the metal layer22, which is an inner metal layer, in the thickness direction.

As shown in FIG,1, the liquid pipe14is formed by the three stacked metal layers21to23, similarly to the condenser13. In the liquid pipe14, the flow path14ris formed by forming a through-hole22Y penetrating through the metal layer22, which is an inner metal layer, in the thickness direction. The liquid pipe14has the pair of pipe walls14wprovided on both sides of the flow path14r. Each pipe wall14wis not formed with a hole or a groove. The liquid pipe14may have a porous body, for example. The porous body is configured to have, for example, first bottomed holes concave from the upper surface of the metal layer22, which is an inner metal layer, second bottomed holes concave from the lower surface of the metal layer22, and pores formed by causing the first bottomed holes and the second bottomed holes to partially communicate with each other. The porous body is configured to guide the working fluid C condensed in the condenser13to the evaporator (refer toFIG.2) by a capillary force generated in the porous body20, for example. In addition, although not shown, the liquid pipe14is provided with an injection port for injecting the working fluid C (refer toFIG.2). However, the injection port is closed by a sealing member, so that an inside of the loop-type heat pipe main body10is kept airtight.

The evaporator11shown inFIG.2is formed by the three stacked metal layers21to23(refer to FIG,1), similarly to the condenser13. The evaporator11may have a porous body, similarly to the liquid pipe14, for example. For example, in the evaporator11, a porous body provided in the evaporator11is formed in a comb-teeth shape. In the evaporator11, a region in which the porous body is not provided has a space.

In this way, the loop-type heat pipe main body10is configured by the three stacked metal layers21to23(refer toFIG.1). Note that, the number of the stacked metal layers is not limited to three layers, and may be four or more layers.

(Configuration of First Magnet50)

The first magnet50is provided in the condenser13of the loop-type heat pipe main body10. The condenser13is provided with, for example, a plurality of (six, in the present embodiment) first magnets50. Each of the first magnets50is embedded in the condenser13, for example. Each of the first magnets50is embedded in the pipe wall13wof the condenser13, for example. In other words, each of the first magnets50is provided so as not to overlap the flow path15, specifically, the flow path13r, in the top view, for example. The first magnets50are provided in both the pair of pipe walls13w, for example.

As shown inFIG.1, each of the first magnets50is provided to penetrate through the pipe wall13wof the condenser13in the thickness direction (here, Z-axis direction), for example. For example, the pipe wall13wis provided with a plurality of through-holes13X penetrating through the pipe wall13win the thickness direction. Each of the first magnets50is accommodated in each through-hole13X, for example. A side surface of each of the first magnets50is in close contact with an inner surface of each through-hole13X, for example. The side surface of each of the first magnets50is in close contact with the inner surface of each through-hole I3X over an entire circumference of the first magnet50in a circumferential direction, for example. Note that, the side surface of each of the first magnets50and the inner surface of each through-hole13X may be in direct contact with each other or may be in contact with each other via an adhesive member or the like. An upper surface of each of the first magnets50is exposed from, for example, the upper surface of the metal layer21, i.e., the first facing surface13A. The upper surface of each of the first magnets50is formed flush with the first facing surface13A, for example. A lower surface of each of the first magnets50is exposed from the lower surface of the metal layer23, for example. The lower surface of each of the first magnets50is formed flush with the lower surface of the metal layer23, for example.

A planar shape of each of the first magnets50can be formed to have arbitrary shape and size. As shown inFIG.2, the planar shape of each of the first magnets50of the present embodiment is formed in a circular shape. That is, each of the first magnets50of the present embodiment is formed in a cylindrical shape. The plurality of first magnets50are provided side by side along one direction (here, X-axis direction) of a plane direction orthogonal to the thickness direction (here, Z-axis direction) of the condenser13, for example. The plurality of first magnets50are provided spaced apart from each other in the X-axis direction, for example. In the condenser13of the present embodiment, on each of both sides of the flow path13r(specifically, flow path r2) in the Y-axis direction, three first magnets50are provided spaced apart from each other in the X-axis direction. The first magnet50provided in one pipe wall13wand the first magnet50provided in the other pipe wall13ware provided to sandwich the flow path13rfrom both sides in the Y-axis direction. For example, the first magnet50provided in one pipe wall13wand the first magnet50provided in the other pipe wall13ware provided at the same positions in the X-axis direction. Note that, the first magnet50provided in one pipe wall13wand the first magnet50provided in the other pipe wall13wmay be provided at positions different from each other in the X-axis direction.

As the first magnet50, for example, a samarium cobalt magnet, an alnico magnet, or the like can be used. As the first magnet50, for example, it is preferably to use a magnet with relatively small demagnetization (reduction in magnetic force) due to heat, i.e., relatively small thermal demagnetization. The first magnet50of the present embodiment is a samarium cobalt magnet with small thermal demagnetization.

(Configuration of Heat Dissipation Plate30)

As shown inFIG.1, the heat dissipation plate30is fixed to the outer surface of the loop-type heat pipe main body10. The heat dissipation plate30is fixed to an outer surface of the condenser13of the loop-type heat pipe main body10, for example. The heat dissipation plate30is fixed to the outer surface of the condenser13by a magnetic attraction force generated between the first magnet50and the second magnet60, for example. The heat dissipation plate30is provided at a position overlapping the condenser13, in the top view, for example. The heat dissipation plate30is thermally connected to the first facing surface13A of the condenser13, for example. The heat dissipation plate30is formed in a flat plate shape, for example. The heat dissipation plate30has a rectangular shape in the top view, for example. A planar shape of the heat dissipation plate30is formed to be larger than a planar shape of the condenser13, for example. The heat dissipation plate30is also referred to as a heat spreader. The heat dissipation plate30is thermally connected to the first facing surface13A of the condenser13, so that it has, for example, a function of dispersing a density of heat from the condenser13.

As a material of the heat dissipation plate30, a material having favorable thermal conductivity may be used, for example. As the heat dissipation plate30, a substrate made of copper (Cu), silver (Ag), aluminum (Al) or an alloy thereof can be used. As the heat dissipation plate30, for example, a substrate made of ceramics such as alumina or aluminum nitride, or an insulating material or semiconductor material having high thermal conductivity such as silicon can also be used. Note that, a thickness of the heat dissipation plate30in the Z-direction may be set to about 500 μm to 1000 μm, for example. The thickness of the heat dissipation plate30is formed thicker than an overall thickness of the loop-type heat pipe main body10, for example.

The heat dissipation plate30has a second facing surface30A (here, lower surface) facing the first facing surface13A of the condenser13. The second facing surface30A faces the first facing surface13A in the Z-axis direction. The second facing surface30A is thermally connected to the first facing surface13A, for example. The second facing surface30A is in direct contact with the first facing surface13A, for example. That is, the second facing surface30A is in contact with the first facing surface13A, so that the heat dissipation plate30of the present embodiment is thermally connected to the loop-type heat pipe main body10.

(Configuration of Second Magnet60)

The second magnet60is provided in the heat dissipation plate30. The heat dissipation plate30is provided with, for example, a plurality of second magnets60. The heat dissipation plate30is provided with the same number (here, six) of second magnets60as the first magnets50. Each of the second magnets60is embedded in the heat dissipation plate30, for example. Each of the second magnets60is provided to face each of the first magnets50in the Z direction. A planar shape of each of the second magnets60can be formed to have arbitrary shape and size. The planar shape of each of the second magnets60of the present embodiment is formed in a circular shape, similarly to the planar shape of the first magnet50. That is, each of the second magnets60of the present embodiment is formed in a cylindrical shape.

Each of the second magnets60is provided to penetrate through the heat dissipation plate30in the thickness direction, for example. For example, the heat dissipation plate30is provided with a plurality of through-holes30X penetrating through the heat dissipation plate30in the thickness direction. Each of the second magnets60is accommodated in each through-hole30X, for example. A side surface of each of the second magnets60is in close contact with an inner surface of each through-hole30X, for example. The side surface of each of the second magnets60is in close contact with the inner surface of each through-hole30X over an entire circumference of the second magnet60in a circumferential direction, for example. Note that, the side surface of each of the second magnets60and the inner surface of each through-hole30X may be in direct contact with each other or may be in contact with each other via an adhesive member or the like. A lower surface of each of the second magnets60is exposed, for example, from the second facing surface30A. The lower surface of each of the second magnets60is formed flush with the second facing surface30A, for example. An upper surface of each of the second magnets60is exposed from the upper of the heat dissipation plate30, for example. The upper surface of each of the second magnets60is flush with the upper surface of the heat dissipation plate30, for example.

As the second magnet60, for example, a samarium cobalt magnet, an alnico magnet, or the like can be used. As the second magnet60, for example, a magnet having relatively small thermal demagnetization is preferably used. The second magnet60may be a magnet of the same type as the first magnet50or a magnet different from the first magnet50. The second magnet60of the present embodiment is a samarium cobalt magnet with small thermal demagnetization.

The first magnet50and the second magnet60are provided such that different magnetic poles face to each other. For example, the first magnet50and the second magnet60are provided such that an N pole of the first magnet50and an S pole of the second magnet60face to each other. For example, the first magnet50and the second magnet60are provided such that an S pole of the first magnet50and an N pole of the second magnet60face to each other. In the present embodiment, the N pole is magnetized on an upper part of the first magnet50and the S pole is magnetized on a lower part of the second magnet60. For this reason, when the upper part of the first magnet50and the lower part of the second magnet60come close to each other, a magnetic attraction force with which the first magnet50and the second magnet60try to attract each other is generated between the first magnet50and the second magnet60. By this magnetic attraction force, the first magnet50and the second magnet60are attracted to each other. In the loop-type heat pipe of the present embodiment, in a state in which the upper surface of the first magnet50and the lower surface of the second magnet60are in direct contact with each other, the first magnet50and the second magnet60are magnetically attracted to each other. Thereby, the heat dissipation plate30is fixed on the condenser13of the loop-type heat pipe main body10. That is, the heat dissipation plate30is fixed on the condenser13by the attraction force generated between the first magnet50and the second magnet60. In other words, the types, numbers, sizes, and the like of the first magnet50and the second magnet60are set so that the heat dissipation plate30can be fixed on the condenser13. Here, in the loop-type heat pipe LH1of the present embodiment, the first facing surface13A of the condenser13and the second facing surface30A of the heat dissipation plate30come into direct contact with each other, so that the condenser13and the heat dissipation plate30are thermally connected to each other. Thereby, a path through which heat is conducted from the condenser13to the heat dissipation plate30is formed. Therefore, the heat in the condenser13can be efficiently dissipated by the heat dissipation plate30. For this reason, it is possible to efficiently cool the heat-generating component100(referFIG.3), and to favorably suppress the heat generated by the heat-generating component100from exceeding the heat tolerance of the heat-generating component100.

Next, the effects of the present embodiment are described.

(1) The heat dissipation plate30is thermally connected to the condenser13. According to this configuration, a path through which heat is conducted from the condenser13to the heat dissipation plate30is formed. Thereby, the heat in the condenser13can be efficiently dissipated by the heat dissipation plate30. For this reason, the heat dissipation property in the loop-type heat pipe main body10and the heat dissipation plate30, i.e., the heat dissipation property in the loop-type heat pipe LH1can be improved. As a result, the heat-generating component100can be efficiently cooled.

(2) The condenser13is provided with the first magnet50, and the heat dissipation plate30is provided with the second magnet60facing the first magnet50. The first magnet50and the second magnet60are provided such that different magnetic poles face to each other. According to this configuration, the heat dissipation plate30can be fixed on the condenser13of the loop-type heat pipe main body10by the magnetic attraction force (adsorption force) generated between the first magnet50and the second magnet60. For this reason, the heat dissipation plate30can be fixed on the condenser13without using a screw, an adhesive or the like, Here, in a case of a fixing method in which a screw is used, when the torque required for fastening the screw increases, there is a concern that the condenser13may be deformed or distorted. In addition, in a case of a fixing method in which an adhesive is used, an adhesive layer is interposed between the condenser13and the heat dissipation plate30. However, in general, since the adhesive layer has low thermal conductivity, there is a problem that the thermal conductivity from the condenser13to the heat dissipation plate30is lowered, as compared to a case in which the adhesive layer is not provided. On the other hand, in the loop-type heat pipe LH1of the present embodiment, the heat dissipation plate30can be fixed on the condenser13by the attraction force of the first magnet50and the second magnet60without using a screw or an adhesive. For this reason, it is possible to favorably suppress deformation and distortion from being generated in the condenser13, and to favorably suppress the thermal conductivity from the condenser13to the heat dissipation plate30from being lowered.

(3) The first magnet50is provided in the condenser13of the loop-type heat pipe main body10. According to this configuration, the first magnet50can be provided in the condenser13having a large area for heat dissipation. For this reason, an installation area of the first magnet50can be easily and widely secured. In addition, the condenser13configured to dissipate heat generated in the heat-generating component100is provided with the first magnet50, so that heat can be efficiently dissipated to the heat dissipation plate30.

(4) The second facing surface30A of the heat dissipation plate30is made to be in contact with the first facing surface13A of the condenser13. According to this configuration, the first facing surface13A and the second facing surface30A are in direct contact with each other, so that the condenser13and the heat dissipation plate30are thermally connected to each other. Therefore, since a member having low thermal conductivity, such as an adhesive layer, is not interposed between the first facing surface13A and the second facing surface30A, it is possible to favorably suppress the thermal conductivity from the condenser13to the heat dissipation plate30from being lowered.

(5) The first magnet50is embedded in the condenser13. According to this configuration, it is possible to favorably suppress the size of the loop-type heat pipe main body10from being increased in the Z-axis direction due to the first magnet.50provided.

(6) The first magnet50is formed to penetrate through the condenser13in the thickness direction. According to this configuration, the thickness of the first magnet50can be easily formed to be thick.

Other Embodiments

The above embodiment can be changed and implemented as follows. The above embodiment and the following modified embodiments can be implemented in combination with each other within a technically consistent range.

In the above embodiment, the first facing surface13A of the condenser13and the second facing surface30A of the heat dissipation plate30are made to be in direct contact with each other. However, the present invention is not limited thereto.

For example, as shown inFIG.4, a heat conduction member70may be interposed between the first facing surface13A. of the condenser13and the second facing surface30A of the heat dissipation plate30. In this case, the heat dissipation plate30is thermally connected to the condenser13via the heat conduction member70.

(Configuration of Heat Conduction Member70)

As a material of the heat conduction member70, for example, a thermal interface material (TIM) can be used. As the material of the heat conduction member70, for example, soft metal such as indium (In) and silver, silicone gel or an organic resin binder containing a metal filler, graphite, or the like can be used.

The heat conduction member70has a first end face70A facing the first facing surface13A of the condenser13, and a second end face70B facing the second facing surface30A of the heat dissipation plate30. At least one of the first end face70A and the second end face70B of the heat conduction member70is formed as a non-adhesive surface, for example. In the heat conduction member70of the present modified embodiment, both the first end face70A and the second end face70B are formed as non-adhesive surfaces. For this reason, the first end face70A of the heat conduction member70is not bonded to the first facing surface13A of the condenser13, and the second end face70B of the heat conduction member70is not bonded to the second facing surface30A of the heat dissipation plate30. However, the first end face70A of the heat conduction member70is in contact with the first facing surface13A so as to be thermally connectable to the first facing surface13A. of the condenser13. in addition, the second end face70B of the heat conduction member70is in contact with the second facing surface30A so as to be thermally connectable to the second facing surface30A of the heat dissipation plate30. Note that, a thickness of the heat conduction member70may be set to about 20 μm to 100 μm, for example.

The heat conduction member70is provided, for example, on a part of the second facing surface30A. The heat conduction member70is provided, for example, on an entire surface of the first facing surface13A. The heat conduction member70is provided to cover an entire surface of the first facing surface13A, for example. The heat conduction member70is provided to overlap the first magnet50in the top view, for example. The heat conduction member70is provided to overlap the second magnet60in the top view, for example, The heat conduction member70is provided to overlap the flow path13rin the top view, for example.

In the present modified embodiment, the first magnet50and the second magnet60are not in direct contact with each other. Even in this case, the heat dissipation plate30is fixed on the condenser13by the attraction force generated between the first magnet50and the second magnet60. In other words, even when the first magnet50and the second magnet60are not in direct contact with each other, the types, numbers, sizes, and the like of the first magnet50and the second magnet60are set so that the heat dissipation plate30can be fixed on the condenser13.

In the present modified embodiment, the heat conduction member70is interposed between the first facing surface13A of the condenser13and the second facing surface30A of the heat dissipation plate30. The heat conduction member70can reduce a contact thermal resistance between the first facing surface13A and the second facing surface30A, and can smoothly conduct heat from the condenser13to the heat dissipation plate30. For this reason, the heat in the condenser13can be efficiently conducted to the heat dissipation plate30via the heat conduction member70.

In addition, both the first end face70A and the second end face70B of the heat conduction member70are formed as non-adhesive surfaces. For this reason, it is possible to suppress interposition of an adhesive layer with low thermal conductivity between the condenser13and the heat dissipation plate30. Therefore, it is possible to favorably suppress the thermal conductivity from the condenser13to the heat dissipation plate30from being lowered.

In the modified embodiment shown inFIG.4, either the first end face70A or the second end face7013of the heat conduction member70may be used as an adhesive surface.

In the modified embodiment shown inFIG.4, both the first end face70A and the second end face70B of the heat conduction member70may be used as adhesive surfaces.

In the modified embodiment shown inFIG.4, although the heat conduction member70is provided on the entire surface of the first facing surface13A of the condenser13, the present invention is not limited thereto.

For example, as shown inFIG.5, the heat conduction member70may be provided on only a part of the first facing surface13A. The heat conduction member70of the present modified embodiment is provided so as not to overlap the first magnet50in the top view. The heat conduction member70of the present modified embodiment is provided so as not to overlap the second magnet60in the top view The heat conduction member70of the present modified embodiment is provided to overlap the flow path13rin the top view. Note that, in the present modified embodiment, an air layer is interposed between the first magnet50and the second magnet60.

In the above embodiment, the first magnet50is formed to penetrate through the condenser13in the thickness direction. However, the present invention is not limited thereto.

For example, as shown inFIG.6, the first magnet50may be formed so as not to penetrate through the condenser13in the thickness direction. In this case, for example, the pipe wall13wof the condenser13is provided with a plurality of concave portions13Y. Each concave portion13Y is formed so as not to penetrate through the condenser13in the thickness direction. Each concave portion13Y is formed to be concave from the first facing surface13A toward the lower surface of the condenser13, for example. Each concave portion13Y is formed to penetrate through the metal layers21and22among the metal layers21,22and23in the thickness direction, for example. Each of the first magnets50is accommodated in each concave portion13Y. The side surface of each of the first magnets50is in close contact with an inner surface of each concave portion13Y for example. Note that, the side surface of each of the first magnets50and the inner surface of each concave portion13Y may be in direct contact with each other or may be in contact with each other via an adhesive member or the like.

A depth of the concave portion13Y shown inFIG.6can be changed as appropriate. For example, the concave portion13Y may be formed to penetrate through the metal layer21among the metal layers21,22and23in the thickness direction.

The concave portion13Y shown inFIG.6may be formed to be concave from the lower surface of the condenser13, i.e., the lower surface of the metal layer23toward the first facing surface13A.

In the above embodiment, the second magnet60is formed to penetrate through the heat dissipation plate30in the thickness direction. However, the present invention is not limited thereto.

For example, as shown inFIG.6, the second magnet60may be formed so as not to penetrate through the heat dissipation plate30in the thickness direction. In this case, for example, the heat dissipation plate30is provided with a plurality of concave portions30Y. Each concave portion30Y is formed so as not to penetrate through the heat dissipation plate30in the thickness direction. Each concave portion30Y is formed to be concave from the second facing surface30A toward the upper surface of the heat dissipation plate30, for example. A bottom surface of each concave portion30Y is provided in the middle of the heat dissipation plate30in the thickness direction. Each of the second magnets60is accommodated in each concave portion30Y. The side surface of each of the second magnets60is in close contact with an inner surface of each concave portion30Y, for example. Note that, the side surface of each of the second magnets60and the inner surface of each concave portion30Y may be in direct contact with each other or may be in contact with each other via an adhesive member or the like.

A depth of the concave portion30Y shown inFIG.6can be changed as appropriate.

The concave portion30Y shown inFIG.6may be formed to be concave from the upper surface of the heat dissipation plate30toward the second facing surface30A.

In the above embodiment, the upper surface of the first magnet50is formed to be flush with the first facing surface13A. However, the present invention is not limited thereto.

For example, as shown inFIG.7, the first magnet50may be formed to protrude toward the second facing surface30A beyond the first facing surface13A. In this case, the upper part of the first magnet50protrudes upward beyond the first facing surface13A. At this time, a protrusion amount of the first magnet50from the first facing surface13A is set to be equal to or smaller than the thickness of the heat conduction member70. Thereby, even when the first magnet50protrudes upward beyond the first facing surface13A, the condenser13and the heat dissipation plate30can be favorably thermally connected to each other via the heat conduction member70,

In the above embodiment, the upper surface of the second magnet60is formed to be flush with the second facing surface30A. However, the present invention is not limited thereto.

For example, as shown inFIG.7, the second magnet60may be formed to protrude toward the first facing surface13A beyond the second facing surface30A. In this case, the lower part of the second magnet60protrudes downward beyond the second facing surface30A. At this time, a protrusion amount of the second magnet60from the second facing surface30A is set to be equal to or smaller than the thickness of the heat conduction member70. Further, in the modified embodiment shown inFIG.7, a total amount obtained by summing the protrusion amount of the first magnet50from the first facing surface13A and the protrusion amount of the second magnet60from the second facing surface30A is set to be equal to or smaller than the thickness of the heat conduction member70. Thereby, even when the first magnet50protrudes beyond the first facing surface13A and the second magnet60protrudes beyond the second facing surface30A, the condenser13and the heat dissipation plate30can be favorably thermally connected to each other via the heat conduction member70.

In the above embodiment, the lower surface of the first magnet50is formed to be flush with the lower surface of the condenser13. However, the present invention is not limited thereto. For example, the lower part of the first magnet50may be formed to protrude downward beyond the lower surface of the condenser13. In addition, for example, the lower part of the first magnet50may be formed to be located closer to the first facing surface13A side than the lower surface of the condenser13.

In the above embodiment, the upper surface of the second magnet60is formed to be flush with the upper surface of the heat dissipation plate30. However, the present invention is not limited thereto. For example, the upper part of the second magnet60may be formed to protrude upward beyond the upper surface of the heat dissipation plate30. In addition, for example, the upper part of the second magnet60may be formed to be located closer to the second facing surface30A side than the upper surface of the heat dissipation plate30.

In the above embodiment, the first magnet50is provided embedded in the condenser13. However, the present invention is not limited thereto. For example, the first magnet50may be provided on the outer surface of the condenser13.

For example, as shown inFIG.8, the first magnet50may be provided on the first facing surface13A of the condenser13. In this case, the thickness of the first magnet50is set to be equal to or smaller than the thickness of the heat conduction member70. In addition, the first magnet50of the present modified embodiment is provided so as not to overlap the heat conduction member70in the top view. Thereby, even when the first magnet50is provided on the first facing surface13A, the condenser13and the heat dissipation plate30can be favorably thermally connected to each other via the heat conduction member70.

In the above embodiment, the second magnet60is provided embedded in the heat dissipation plate30. However, the present invention is not limited thereto. For example, the second magnet60may be provided on the outer surface of the heat dissipation plate30.

For example, as shown inFIG.8, the second magnet60may be provided on the second facing surface30A of the heat dissipation plate30. In this case, the thickness of the second magnet60is set to be equal to or smaller than the thickness of the heat conduction member70. In addition, the second magnet60of the present modified embodiment is provided so as not to overlap the heat conduction member70in the top view. Further, in the modified embodiment shown inFIG.8, a total thickness obtained by summing the thickness of the first magnet50provided on the first facing surface13A and the thickness of the second magnet60provided on the second facing surface30A is set to be equal to or smaller than the thickness of the heat conduction member70. Thereby, even when the first magnet50is provided on the first facing surface13A. and the second magnet60is provided on the second facing surface30A, the condenser13and the heat dissipation plate30can be favorably thermally connected to each other via the heat conduction member70.

For example, as shown in FIG,9, the first magnet50may be provided on a lower surface13B of the condenser13. In this case, the first magnet50may be provided to overlap the flow path13rin the top view. Further, the first magnet50may be provided to partially overlap the second magnet60in the top view.

In the modified embodiment shown inFIG.9, the heat conduction member70may be omitted.

The planar shape of the first magnet50in the above embodiment is not particularly limited. For example, the planar shape of the first magnet50may be formed in an arbitrary shape such as a polygonal shape, a semicircular shape or an elliptical shape.

The planar shape of the second magnet60in the above embodiment is not particularly limited. For example, the planar shape of the second magnet60may be formed in an arbitrary shape such as a polygonal shape, a semicircular shape or an elliptical shape.

The shape of the flow path13rin the condenser13in the above embodiment is not particularly limited.

For example, as shown inFIG.10, the flow path13rmay be formed in a shape having a serpentine part r4meandering in an XY plane. The flow path13rof the present modified embodiment includes a flow path r1extending in the Y-axis direction, a serpentine part r4extending in the X-axis direction while meandering from an end portion of the flow path r1, and a flow path r3extending in the Y-axis direction from an end portion of the serpentine part r4. The first magnet50of the present modified embodiment is provided so as not to overlap the flow path13rin the top view, for example.

In the above embodiment, the first magnets50are provided in both the pair of pipe walls13wof the condenser13. However, the present invention is not limited thereto. For example, the first magnet50may be provided only in one pipe wall13wof the pair of pipe walls13w.

In the above embodiment, the plurality of first magnets50may be formed in different shapes from each other.

In the above embodiment, the plurality of second magnets60may be formed in different shapes from each other.

In the above embodiment, the first magnet50and the second magnet60may be formed in different shapes from each other.

In the above embodiment, the first magnet50is provided in the condenser13of the loop-type heat pipe main body10, and the heat dissipation plate30is thermally connected to the condenser13. However, the present invention is not limited thereto. For example, the first magnet50may be provided in the liquid pipe14and the heat dissipation plate30may be thermally connected to the liquid pipe14. For example, the first magnet50may be provided in the vapor pipe12, and the heat dissipation plate30may be thermally connected to the vapor pipe12.

In the loop-type heat pipe main body10of the above embodiment, the inner metal layer is configured only by the metal layer22of a single layer. That is, the inner metal layer is formed to have a single layer structure. However, the present invention is not limited thereto. For example, the inner metal layer may also be formed to have a stacked structure where a plurality of metal layers is stacked. In this case, the inner metal layer is configured by a plurality of metal layers stacked between the metal layer21and the metal layer23.