JP3912382B2 - Electronic device casing and heat conduction path member used therefor - Google Patents

Description

  The present invention relates to an electronic device casing and a heat conduction path member used therefor, and more particularly to a heat dissipation structure thereof. In recent years, portable electronic devices typified by notebook personal computers (hereinafter abbreviated as personal computers) have become smaller in housing volume as demands for smaller size, lighter weight, and higher performance have increased. In addition, the number of electronic components mounted per unit area on the printed wiring board is increasing, and the amount of heat generated by the electronic components is also increasing. For example, high-speed MPUs (Microprocessor Units) and CPUs (Central Processing Units), even those that are power-saving, are used in excess of 6.5 W, and the amount of heat generated inside the housing tends to increase further. For this reason, in a personal computer or the like, there is a strong demand for ensuring the reliability and stable operation of electronic devices by efficiently radiating the heat generated inside the housing to the outside of the housing.

  The personal computer housing is divided into a main body housing 1 and a display housing 2 as shown in FIGS. 19 and 20, and the main body housing 1 and the display housing 2 are connected by a rotatable hinge 3. Has been.

  The display unit housing 2 has a structure that pivots about the hinge unit 3 to open and close the main unit housing 1 and is closed when not in use, and is opened and held at an arbitrary angle when in use.

  The main body housing 1 includes a main wiring board 4, a sub wiring board 5, an HDD (Hard Disk Drive) 6, and a PCMCIA card (Personal Computer Memory Card Interface Association) on which electronic components such as a high-speed MPU that is a high heating element are mounted. 7, a battery 8 and a keyboard 9 (not shown in FIG. 19, not shown in FIG. 20) are disposed. The other display unit housing 2 is mainly composed of a display panel [LCD, Liquid Crystal Display (LCD). ]] 11 is mounted.

  In the personal computer having such a configuration, the problem of heat generation is the main body housing that generates a large amount of heat. As a means for radiating heat generated inside the main body casing, there is a heat spreader (heat diffusing plate) 10 provided on a high heating element such as an MPU shown in FIG. In addition, there are an air cooling fan, a heat radiating fin, a heat sink, a heat pipe, and a decrease in the number of clock pulses by software.

  In addition, when one end (high temperature part) of the pipe is heated, the heat medium enclosed in the vacuum is vaporized, the heat pipe moves to the other end (low temperature part), and the other end is cooled. It is liquefied and recirculates and circulates in the reflux passage to the high temperature portion by capillary action to move (transport) the heat of the high temperature portion to the low temperature portion.

  Among these, an air cooling fan that generates forced convection and cools it is frequently used as one of the most effective cooling means. Further, since the heat radiation fin has the greatest heat radiation effect under the forced convection and the natural convection, some of the heat radiation fins are exposed outside the casing.

Alternatively, JP-A-8-162576, JP-A-9-6481, JP-A-10-39955, etc. use a combination of a heat pipe and a heat sink to diffuse heat throughout the interior of the main body housing. The structure that dissipates heat and the heat generated inside the main unit case are guided to the hinge part connected to the heat receiving plate and heat pipe, and then moved to the heat sink of the display part case connected to this hinge part. A structure that dissipates heat from the housing is disclosed.
JP-A-8-162576 JP-A-9-6481 JP 10-39955 A

  However, according to such a heat dissipation structure, when an air cooling fan is used, the convection of the air inside the housing deteriorates due to the downsizing and thinning of the electronic device housing or the high-density mounting of electronic components, and the inflow and outflow of air. It is difficult to secure mounting space for roads and air cooling fans.

  Further, the heat radiation fin exposed to the outside has a problem that there is a risk of low-temperature burns if the appearance of the design is deteriorated or if the hand is touched by a too high temperature.

  In addition, when heat is diffused and heat is dissipated inside the housing, there is a problem that the temperature of a low heat-generating component such as an HDD or a PCMCIA card is raised.

  In addition, when heat is radiated from the surface of the PC housing, it is preferable that the surface temperature is somewhat high in terms of heat dissipation effect, but if the surface temperature of the housing exceeds 45 ° C, there is a risk of low temperature burns. There's a problem.

  In the “Method for manufacturing an electronic device casing” disclosed in Japanese Patent Application Laid-Open No. 7-124995, an electronic device casing is lightweight, high-strength, and excellent in heat dissipation by melting and bonding a resin based on a metal substrate such as aluminum. An in-mold method for producing a body is disclosed.

  Therefore, by applying this in-mold method, taking a personal computer housing as an example, an electronic device housing having a heat conduction path in which a high heating element in the main body housing and a heat radiation portion of the display housing are directly connected And the electronic device housing | casing provided with the hinge part with the high heat conductivity which combined the heat pipe is proposed.

  Furthermore, a heat conduction path member that conducts high heat conduction that is manufactured separately and an electronic device housing in which a high heating element in the main body housing and a heat radiating portion of the display housing are connected using the heat conduction path member are proposed.

  In view of the above problems, the heat inside the main unit housing with a large calorific value is transferred to the heat radiating part of the display unit housing with a small calorific value without any trouble in opening and closing the display unit housing, and heat is dissipated to the outside by natural convection. It is an object of the present invention to provide an electronic device casing and a heat conduction path member used therefor.

The heat conduction path member according to claim 1, wherein a plurality of ends of the graphite sheet having anisotropy in the plane direction are connected to a member that generates heat, conducts heat, or dissipates, and is insulated on one or both sides of the graphite sheet. It has a winding part wound with a sheet interposed.

Accordingly, the heat conduction path member is laminated by winding a graphite sheet, since the thickness becomes substantially large, thermal resistance Ru can effectively heat conduction decreases.

  Further, since the bending portion is repeatedly bent around the winding portion, the bending stress generated by the bending is dispersed throughout the winding portion, reducing fatigue due to repeated bending and extending the life.

Further, in the heat conduction path member according to claim 2, the winding portion of the heat conduction path member is wound around a cylindrical or cylindrical core, particularly when a plurality of graphite sheets are wound. The diameter dimension is suppressed with high accuracy, and it is possible to prevent deformation of the shape after winding.

  Furthermore, when a cylindrical winding core (pipe) is used, the space can be effectively used by passing a wire through the hollow hole.

According to a third aspect of the present invention, in the electronic device casing, the first casing having a heating element and the second casing having a heat dissipating part for radiating the heat of the heating element of the first casing to the outside. And an electronic device housing in which the second housing is opened and closed by a hinge portion with respect to the first housing, and heat dissipation of the first housing and heat dissipation of the second housing with parts and are connected at a joint according to claim 1 or claim 2, wherein the heat conducting path member, the winding unit distribution such that the winding axis is substantially coincident with the rotation center of the hinge portion Installed and configured.

  As a result, the heat conduction path member is formed by winding a graphite sheet and laminating it, and substantially increasing its thickness to reduce the thermal resistance. Therefore, the heat conduction path member is integrally formed with the heat radiating portion of the conventional second casing. The heat conduction path portion and the heat receiving portion can conduct heat as effectively as possible.

  In addition, since the heat conduction path member has the axial center of the winding portion substantially coincident with the rotation center of the hinge portion, the winding diameter of the winding portion repeatedly expands and contracts as the second casing is opened and closed. Thus, the bending stress is dispersed throughout the winding part. Therefore, fatigue of the heat conduction path member accompanying opening and closing of the second housing is reduced, and the life can be extended.

Since the heat conduction path member has a winding part wound with a graphite sheet to increase the heat conduction cross-sectional area, the heat conduction path member is used to dissipate heat from the heating element of the main body case and the display case. Even if it is connected to a separate unit, it can conduct heat as effectively as a heat conduction path unit that is integrally formed with a conventional heat radiation unit, and greatly cools high heating elements such as MPU inside the main unit housing An effect is acquired and the temperature rise can be decreased.

  In addition, the winding portion of the heat conduction path member disperses bending stress due to repetitive bending accompanying opening and closing of the display unit housing, thereby reducing fatigue. It exhibits an extremely useful effect in the industry that the number of times of opening and closing can be greatly improved.

    Hereinafter, the gist of the present invention will be described in detail based on each embodiment shown in the drawings. The same components as those in FIGS. 19 and 20 are denoted by the same reference numerals, and the description thereof is omitted.

  First, the heat dissipation structure of the personal computer casing of the first embodiment will be described.

  As shown in FIG. 19, the personal computer housing is a main body housing incorporating a printed wiring board, an HDD, a PCMCIA card, a battery, a keyboard and the like on which an MPU is mounted, and a display portion on which an LCD is mainly mounted. It is comprised with a housing | casing, and couple | bonds a main-body part housing | casing and a display part housing | casing so that opening and closing is possible by a hinge part. In this case, the hinge portion is a well-known general hinge structure in which a pin and a pin hole are engaged and rotated.

  The heat dissipating structure of the PC case moves the heat inside the main unit case with a large amount of heat generation to the display unit case with a small amount of heat generation and efficiently dissipates it. The heat conduction path connecting the body and the heat radiating part of the display unit housing is integrated.

  Thereby, the thermal resistance of the heat conduction path is reduced, and the heat generated inside the main body housing is efficiently conducted and diffused directly to the heat radiating portion of the display housing through the heat conduction path, Heat is dissipated to the outside by natural convection from the entire heat dissipation part.

  As shown in FIG. 1, a box-shaped display unit housing 20 having a shallow bottom extends from a heat radiating unit 21 constituting most of the bottom of the display unit housing 20 to one end of the heat radiating unit 21 in a tongue shape. And the heat receiving path portion that extends further from the heat conduction path portion 22 and receives heat (collected heat) generated in the main body housing 24 to conduct heat to the heat conduction path portion 22. 23 and a single unit.

  The heat dissipating part 21 receives the heat moved through the heat conduction path part 22 and diffuses it widely, and dissipates heat to the outside by natural convection. Therefore, the heat radiation part 21 is made as wide as possible to increase the heat radiation effect.

  The heat conduction path portion 22 extends over the display unit casing 20 and the main unit casing 24 and is easily bent in a double-fold shape according to the opening and closing of the display unit casing 20 (see reference numeral 22 in FIG. 6). The heat from the heat receiving unit 23 is directly conducted to the heat radiating unit 21 of the display unit housing 20.

  The heat receiving portion 23 is screwed on a heat spreader (see reference numeral 10 in FIG. 19) made of a highly heat conductive metal, for example, aluminum, which is attached in close contact with a heating element provided in the main body housing 24. To receive heat generated inside the main body casing, mainly heat generated by a high heating element such as MPU. The contact surface with the heat spreader is coated with a thermal compound in order to improve heat conduction.

  Next, a method for manufacturing the display housing will be described.

  As shown in FIG. 2, the heat radiating portion 21 of the display unit housing 20 has a high thermal conductivity metal substrate 25 as a base material (core material), and covers the range of the peripheral edge X on the back surface with a resin 26. A side frame 27 whose outer periphery is raised in a square frame shape, a hinge mounting portion (not shown), and a screw hole boss and a reinforcing rib provided as necessary are integrally formed by injection molding with the same resin 26. The surface of the metal substrate 25 is exposed to the outside except for the peripheral edge portion X covered with the resin 26.

  Further, in order to integrally form a heat conduction path with the main body casing, the heat radiating section 21 is a high heating element of the main body casing 24 shown in FIG. The heat conduction path portion 22 and the heat receiving portion 23 are formed so as to extend in the direction.

  FIGS. 3A and 3B show the injection molding process of the display unit casing.

  Since heat conduction and heat dissipation are mainly performed by a metal substrate as a base material, it is effective to use copper (thermal conductivity 400 W / mK) as the material of the metal substrate. Further, although the thermal conductivity is inferior to copper, the display unit housing can be strengthened by using aluminum (thermal conductivity 230 W / mK).

  In the case of copper, the thickness is 0.1 to 0.3 mm, and in the case of aluminum, the thickness is about 0.1 to 0.6 mm. In this embodiment, copper having a thickness of 0.2 mm is used. In addition, copper may be a copper alloy and aluminum may be an aluminum alloy, and the following copper and aluminum include those alloys.

  In FIG. 3 (a), the metal substrate 25 serving as a base material is degreased and washed, and then adheres the molten resin at the time of molding. Is uniformly applied in a thickness of 20 μm by screen printing or spraying, and then is removed by press working or the like into a shape for forming the heat radiating part 21, the heat conduction path part 22 and the heat receiving part 23 shown in FIG.

  Further, the metal substrate 25 is provided with a positioning hole 29 for positioning in the molding die in the next injection molding process. It should be noted that the metal substrate may be reversed so that the adhesive is applied after the metal substrate is first removed.

  In FIG. 3 (b), the metal substrate 25 is positioned and set on the molding die 30.

  The molding die 30 used here includes a lower die 30a and an upper die 30b. The lower mold 30a includes a fixed pin 32 having a step slidable in a guide hole 31 formed at a position corresponding to the positioning hole 29 of the metal substrate 25, and a coil spring inserted into a small diameter portion of the fixed pin 32. 33 is urged in the direction opposite to the direction in which the resin 26 enters. The urging force is designed to be pushed back by the injection pressure of the resin 26.

  The upper mold 30 b that is paired with the lower mold 30 a includes a runner 34 that injects the resin 26 concentrically with the fixing pin 32. Further, a stopper 35 for receiving the fixing pin 32 pushed back by the injection pressure of the resin 26 is provided, and the cavity 36 is formed by clamping the lower mold 30a and the upper mold 30b.

  In addition, naturally the heat conduction path | pass part and heat receiving part which are not illustrated extended from the thermal radiation part are taken out outside from the metal mold | die for shaping | molding in the structure which does not carry out resin molding simultaneously.

  The resin 26 is thermoplastic and uses, for example, ABS-PC (acrylonitrile butadiene styrene) resin (20% by weight of CF (Carbon Fiber) filled). The injection molding conditions are a resin melting temperature of 240 DEG C., an injection pressure of 600 kgf / cm @ 2, and an injection time of 1.5 seconds.

  In FIG. 4A, when the resin 26 is injected from the runner 34, the fixing pin 32 is pushed back by the injection pressure of the resin 26 and comes into contact with the stopper 35. At this time, the upper end surface of the fixing pin 32 is designed in advance so as to coincide with the surface of the metal substrate 25.

  When the resin 26 fills the cavity 36, the positioning hole 29 is blocked by the resin 26. Therefore, there is no need for means and process for closing the fixing pin hole 29, the molding becomes easy, and the structure of the molding die can be simplified.

  4B, after the resin 26 is cooled and hardened, the display unit housing 20 is opened by using a knockout pin (not shown) and taken out. The display unit housing 20 completed by these steps is integrally provided with a heat conduction path unit and a heat receiving unit made of a metal substrate (not shown) extending from the heat radiation unit 21.

  In order to evaluate the heat dissipation effect of the display unit case manufactured in this way, as shown in FIGS. 5 and 6, the display unit case 20 is coupled to the main unit case 24 with a hinge portion 37 to be connected to a personal computer. The temperature was measured by assembling and operating a personal computer.

  Note that the power consumption during the operation of the personal computer is 8.9 W (including 5 W of MPU), power supply 2.8 W, HDD 2.5 W, and PCMCIA 1.5 W, each generating corresponding heat.

  And in order to compare the heat dissipation effect, a comparative example 1 is prototyped.

  As shown in FIG. 7, the display unit housing 40 of this comparative example 1 has a structure in which the heat radiating part 41 is not manufactured integrally with the heat receiving part and the heat conduction path part, but is manufactured separately. To do. That is, the heat radiating part 41 has a shape in which the heat conduction path part 42 and the heat receiving part 43 are separated, and is manufactured by the same in-mold method as in the first embodiment.

  The heat conduction path portion 42 and the heat receiving portion 43 are made of separate metal substrates and copper having a thickness of 0.2 mm, and the end portion is overlapped with the metal surface of the edge of the heat radiating portion 41 to adhere styrene rubber. Glue with the agent.

  The display housing 40 is coupled to the same main body housing 24 as the first embodiment by a hinge portion 37 and assembled to a personal computer, and the heat receiving portion 43 is fixed to the heat spreader as in the first embodiment. Thus, the temperature during operation of the personal computer was measured.

  As a result, in the first example, the temperature of the MPU decreased by 5 ° C compared to the comparative example 1, and the surface temperature of the heat radiating portion of the display unit housing was below 35 ° C in the vicinity of the highest heat inflow portion. It was possible to achieve a temperature reference of 45 ° C. or lower, which is the temperature reference for the surface of the personal computer casing.

  In Comparative Example 1, the heat conduction path portion is bonded and connected to the heat radiation portion with an adhesive, so that the thermal resistance is larger than that of the first embodiment, and the heat conduction path is seamlessly integrated. It was confirmed that the heat-dissipating structure of Example 1 had better heat conduction efficiency than Comparative Example 1. Of course, even in Comparative Example 1, the surface temperature of the heat radiating portion is below 40 ° C. in the vicinity of the heat inflow portion and satisfies the temperature reference of 45 ° C. or less.

  Further, the metal substrate in the first embodiment is not copper having a thickness of 0.2 mm, but an equivalent heat dissipation effect can be obtained even if it is replaced by aluminum having a thickness of 0.4 mm. It was confirmed that sufficient mechanical strength could be secured.

  In addition, the metal substrate of the heat radiating part, the heat conduction path part and the heat receiving part is a table excluding the front and back surfaces excluding the surface of the heat radiating part on the outside air side and the connecting surface with the heat spreader of the heat receiving part, or the surface excluding only the connecting surface with the heat spreader of the heat receiving part. Even when 0.2 mm of resin was coated on the back surface and the metal surface of the heat receiving part was directly connected to the heat spreader, it was confirmed that there were almost the same operations and effects as in the first example.

  Next, a second embodiment will be described.

  Although not shown, the display unit housing of the second embodiment uses a graphite sheet having a thickness of 0.1 mm as a base material instead of the metal substrate of the first embodiment, and the first embodiment The display unit casing is manufactured by the in-mold method in the same manner as described above.

  The graphite sheet covers the entire inner surface of the heat dissipating part, the heat conduction path part and the heat receiving part and the opposite surface of the heat conduction path part with a resin having a thickness of 0.2 mm, and in particular prevents the edge part from tearing. . Further, the heat receiving portion does not cover the surface of the graphite sheet that contacts the heat spreader with resin, and directly adheres the graphite sheet surface to the heat spreader.

  The temperature during operation of the personal computer using this display unit casing was measured. As a result, compared with the comparative example 1, the temperature of MPU fell by 7 degreeC and the surface temperature of the thermal radiation part of the display part housing | casing was less than 35 degreeC.

  This is because the thermal conductivity in the plane direction of the graphite sheet is 600 W / mK, the thermal conductivity in the thickness direction is 5 W / mK, and there is anisotropy in thermal conductivity, which is superior to copper and aluminum. is there.

  Utilizing such anisotropy in the plane direction, by making the anisotropy direction substantially coincide with the heat conduction direction, the thermal resistance in the heat conduction direction can be reduced. The heat generated by the high heating element can be effectively conducted along the heat conduction path from the heat receiving part to the heat radiating part through the heat conduction path part.

  The heat conduction from the heat spreader to the heat receiving part is mainly in the surface direction of the graphite sheet in direct contact with the heat spreader surface rather than the heat conduction in the thickness direction of the graphite sheet because the thickness of the graphite sheet is as thin as 0.1 mm. Done.

  Also, the graphite sheet of the heat conduction path part is coated with resin on both sides, and the thermal conductivity in the thickness direction of the graphite sheet itself is small, so the thermal effect on other parts in the vicinity of the heat conduction path part is reduced, The temperature of the printed wiring board disposed below the heat conduction path portion was reduced by about 3 ° C. as compared to the first example.

  Next, a third embodiment will be described.

  As shown in FIGS. 8A and 8B, the display unit housing 50 is different from the first embodiment only in the heat conduction path unit 52. FIG. That is, the heat receiving portion 53 constituted by the metal substrate extending from the heat radiating portion 51 remains the metal substrate (copper) as in the first embodiment, and only the heat conduction path portion 52 is shown in FIG. ) As shown in the figure, a PET sheet 56 (Polyethylene Terephthalete) having a thickness of 50 μm is formed on both sides of a 0.2 mm thick copper (or aluminum having a thickness of 0.4 mm), which is a metal substrate, in a separate process from the in-mold process. Adhere Sheet.

  As shown in FIG. 5A, the display unit housing 50 was incorporated in a personal computer, and the temperature during operation was measured.

  As a result, the temperature of the MPU is 7 ° C lower than that of the comparative example 1, the surface temperature of the heat radiating portion of the display unit housing is lower than 35 ° C, and the base material of the second embodiment is a graphite sheet. The same heat dissipation effect was obtained.

  Moreover, in this 3rd Example, since the PET sheet | seat is adhere | attached on both surfaces of the metal substrate which is a heat conductive path part, the printed wiring board under the heat conductive path part and the same as 2nd Example The influence of heat on the electronic components was reduced, and the temperature of the printed wiring board decreased by about 3 ° C. compared to the first example.

  Next, a fourth embodiment will be described.

  As shown in FIG. 6, the heat conduction path unit 22 is disposed across the display unit housing 20 and the main unit housing 24, and is therefore repeatedly bent as the display unit housing 20 is opened and closed. The

  Therefore, repeated opening / closing evaluation of the display housing was performed as follows.

  Although not shown in the figure, when a copper plate having a thickness of 0.2 mm is used as a base material for the heat conduction path portion, an insulating sheet such as polyethylene terephthalate having a thickness of 0.1 mm (for example, 0.1 mm thick) A curvature test was repeatedly performed when the PET sheet was adhered.

  As a result, in the case of a graphite sheet in which a PET sheet is bonded to both surfaces, the number of repeated opening and closing of the display unit housing is improved by about 20% compared to the case of a copper base material, and it can withstand 10,000 times or more of opening and closing. It could be confirmed.

  Next, a fifth embodiment for evaluating the static load strength and heat dissipation of the display unit housing will be described.

  As shown in FIG. 9, the display unit housing 60 is formed by injection-molding the heat radiating unit 61 by an in-mold method using 0.4 mm-thick aluminum (plate) as the first metal substrate 65 as a base material. The first metal substrate 65 is the same as that of the first embodiment in that a heat conduction path portion (not shown) and a heat receiving portion (not shown) are integrally formed.

  However, in the fifth embodiment, in particular, the thickness of the second metal substrate 67 on the resin 66 having a thickness of 0.2 mm coated on the inner surface of the first metal substrate 65 which is the base material of the heat radiating portion 61. The difference is that a 0.1 mm-thick copper is bonded with an epoxy resin adhesive, and the surface of the first metal substrate 65 is the outside air surface.

  As Comparative Example 2, although not shown in the drawings, a display unit housing that does not adhere copper to the inner surface was manufactured, and the static load strength was compared. The measurement is performed by supporting both ends of the long side of the display unit casing, applying a bending load from above to the center, and comparing the bending dimensions of the center at that time.

  As a result, the display unit case having 0.2 mm thick copper bonded to the inner surface has a deflection amount of 1/3 or less compared to the display unit case of Comparative Example 2 in which copper is not bonded. It has been found that a sufficient reinforcing effect can be obtained.

  Further, in the temperature measurement, the temperature of the MPU decreased by 10 ° C. as compared with Comparative Example 2, and the surface temperature of the display unit casing was lower than 35 ° C.

  Next, a sixth embodiment will be described.

  As shown in FIG. 10, the display unit housing 70 includes spherical metal particles 77 a that serve as spacers having an average diameter of 0.2 mm using aluminum having a thickness of 0.4 mm that is the first and second metal substrates 75 and 76. First embodiment with the first metal substrate 75 as the outside surface side, with a base having a space having an air layer 78 of approximately 0.2 mm bonded with an epoxy adhesive 77 mixed with It is manufactured by the in-mold method as well. In this case, the heat conduction path portion and the heat receiving portion are integrally formed by extending only the inner second metal substrate 76 from the heat radiating portion 71 although not shown.

  The air layer 78 is formed by applying an adhesive in one direction with a predetermined distance and a band width in advance to the bonding surface of the first metal substrate 75 and then pressing the second metal substrate 76. The Further, an air vent hole 79 at the time of injection molding is provided at an appropriate position of the second metal substrate 76 that is inside.

  This display housing was incorporated into a personal computer, and the temperature during operation was measured. By providing the air layer in the heat radiating portion, the heat conducted from the heat conduction path portion is further diffused over the entire surface of the heat radiating portion, and the surface temperature of the display unit housing is below 32 ° C.

  Next, a seventh embodiment will be described.

  As shown in FIG. 11, the display unit casing 80 has a space of about 0.5 mm for aluminum and copper, which are first and second metal substrates 85 and 86 having thicknesses of 0.4 mm and 0.2 mm, respectively. In the same manner as in the first embodiment, the substrate is formed by putting a metal net 87 made of aluminum having a thickness of 0.2 mm in this space and using the first metal substrate 85 as the outside surface side. It is manufactured by the in-mold method. The metal net 87 may be copper.

  In this case, although illustration is omitted, the heat conduction path portion and the heat receiving portion are integrally formed by extending only the inner second metal substrate 86 from the heat radiating portion 81. Further, as shown in FIG. 11, an air vent hole 89 at the time of injection molding is provided at an appropriate position of the inner second metal substrate 86.

  Further, after forming, 10% of the internal volume of pure water or Freon 134a or 142b is sealed in the gap space of the metal net 87 as the cooling liquid 88 from the air vent hole 89.

  This display housing was incorporated into a personal computer, and the temperature during operation was measured. The cooling liquid put in the space convects in the space due to the temperature rise and is cooled to generate heat convection, so that the temperature of the MPU is reduced by 12 ° C. and the surface temperature of the display unit housing is 35 ° C. The temperature distribution on the surface of the heat dissipating part was made uniform.

  By the way, in each of the embodiments described above, the heat generated inside the main body casing is directly conducted to the heat radiating portion of the display section casing through the heat conduction path and is dissipated to the outside. A heat dissipation structure for a personal computer will be described in which the heat conduction path from the display unit housing to the heat dissipation unit is replaced with a rotating means capable of moving and relaying heat.

  First, an eighth embodiment will be described.

  FIG. 12 is a plan view showing a heat dissipation structure including the rotating means of one embodiment, and FIG. 13 is an assembled side sectional view of the rotating means in FIG.

  As shown in the figure, the main body housing 24 and the display housing 40 are coupled by two pivotable hinge portions 37 and a pivoting means 90. The rotation means 90 of the present invention is on the right side, and the left hinge portion 37 is a well-known general hinge structure, and its description is omitted.

  The rotating means 90 of the present invention connects first and second heat pipes 91 and 92 having an outer diameter of about 4 mm to both sides thereof. The heat pipe used here is, for example, a commercial product manufactured by Furukawa Electric Co., Ltd., and can transfer (transport) heat from the high temperature part at one end to the low temperature part at the other end as described above.

  The first heat pipe 91 has a high-temperature portion fixed in close contact with a heat spreader 10 (see FIG. 19) fixed to a high heating element such as an MPU installed in the main body housing 24, and an intermediate portion is fixed to the heat spreader. In order to prevent an excessive force from being applied to the high heating element 10 and to serve as an axial center, a fastener (not shown) is firmly fixed to an appropriate position of the main body housing. The low temperature part on the opposite side is inserted into the axial center of the rotating body 93 constituting the rotating side of the rotating means 90 and also serves as the central axis.

  The second heat pipe 92 is inserted into the rotating body 93 that rotates about the first heat pipe 91 as an axis. The low-temperature part on the opposite side is not shown in close contact with the heat radiating part 41 of the display unit housing 40 (without the heat conduction path part 42 and the heat receiving part 43 formed separately as shown in FIG. 7). Secure with fasteners.

  Next, the structure of the rotating means will be described in detail.

  As shown in FIG. 13, the turning means 90 is composed of a highly heat-conductive turning body 93 and a bearing 94.

  The rotating body 93 has a cylindrical shape with an outer diameter of about 20 mm and a length of about 40 mm, and has a hollow hole 93a with an inner diameter of 10 mm formed in the center, and is formed in the low temperature portion of the first heat pipe 91 at the center of the bottom surface of the hollow hole 93a. A conical hole 93b for supporting the conical pointed portion 91a and an insertion hole 93d for fixing the high temperature portion of the second heat pipe 92 to the rear end portion are provided.

  The bearing 94 has a hexagonal bolt shape having a hexagonal head having a diagonal dimension of 20 mm, and has a shaft hole 94 a that is pivotally supported by being inserted through the low temperature portion of the first heat pipe 91. In preparation for the shaft center, the male screw portion 94b is screwed into the screw portion 93c to be fixed in the hollow hole 93a.

  The concavity hole 93b of the rotating body 93 supports the pointed portion 91a of the low temperature portion of the first heat pipe 91 pivotally supported by the shaft hole 94a so as to be centered and reduces the rotational frictional resistance.

  When the rotating body 93 and the bearing 94 are made of a highly thermally conductive metal such as copper or aluminum, the rotating unit 90 has a thermal resistance of 8 ° C / W or less, and the temperature of the MPU decreases by about 4 ° C. did it.

  Furthermore, in order to lower the thermal resistance of the rotating means 90, a plurality of high heat conductive metals such as copper and aluminum (the figure is shown) are formed in the low temperature portion of the first heat pipe 91 inserted into the hollow hole 93a of the rotating body 93. The disc-like fins 95 (four examples) are fitted. For example, the fin 95 has an outer diameter of 9 mm and a thickness of 1 mm.

  Thus, by adding the fin 95, the thermal resistance of the rotation means 90 became 5 degrees C / W or less, and the temperature of MPU could be reduced about 6 degrees C.

  Furthermore, in order to promote heat conduction in the hollow hole 93a of the rotating body 93, silicon fluid having good fluidity is sealed in the hollow hole 93a as the heat conductive fluid 96. In order to prevent leakage of the heat conductive fluid 96, an annular groove is provided on the inner surface of the shaft hole 94a of the bearing 94, and an O-ring 97 is inserted.

  Thus, by additionally enclosing the heat conductive fluid (silicone grease) 96 in the hollow hole 93a, the thermal resistance of the rotating means 90 becomes 1 ° C / W or less, and the temperature of the MPU is about 10 ° C. I was able to decrease.

  Alternatively, by replacing the silicon grease with indium-gallium as the liquid metal 98, the thermal resistance of the rotating means 90 was 1 ° C./W or less, and the temperature of the MPU could be reduced by 13 ° C.

  Since the rotating means configured in this manner is coupled to and fixed to the rotating body of the high temperature part of the second heat pipe fixed to the display unit casing, the display unit casing is connected to the first heat pipe. It can be opened and closed with the low temperature part as the central axis.

  Further, the heat of the high heating element provided in the main body housing is moved to the rotating means by the first heat pipe, and the high heat is transferred from the low temperature portion of the first heat pipe through the heat radiation fin and the heat conductive fluid. Conducts heat efficiently to the conductive rotating body.

  Furthermore, since the heat that has moved to the rotating body moves through the second heat pipe and is conducted and diffused to the heat radiating part of the display unit housing, heat is dissipated by natural convection from the wide heat radiating surface of the heat radiating part to the outside. Temperature rises inside the high heat generator and the main body housing can be suppressed.

  Next, as described above, the heat conduction path section is disposed across the display section casing and the main body section casing, and is therefore repeatedly bent as the display section casing is opened and closed. Since the conduction path portion is fatigued due to repeated bending, there is a certain limit in the number of times the display unit housing can be opened and closed. In order to improve this, a separate heat conduction path member in which the heat conduction path portion and the heat receiving portion are combined was manufactured.

  14 is a perspective view of the first embodiment of the heat conduction path member, FIG. 15 is a development view of FIG. 14, FIG. 15A is a plan view, and FIG. It is sectional drawing.

  The heat conduction path member 12 of the first embodiment shown in FIGS. 14 and 15, that is, 12-1, cuts one end portion of one rectangular graphite sheet 12 a from the center and connects each to the outside. The connecting portion 12a-1 (see the hatched portion in FIG. 15A) is used, and the insulating sheet 12b is bonded to one side of the connecting portion 12a-1 excluding the connecting surface with the outside (the other side) with an adhesive 12c. And a winding portion 13 in which the bonded portion is wound in a spiral tube shape a plurality of times.

  In addition, although the insulating sheet 12b shown in FIG.14 and FIG.15 is bonded together on the single side | surface of the graphite sheet 12a, both surfaces are good. In addition, the insulating sheet 12b may be overlapped and wound without being bonded, but it is preferable to bond the insulating sheet 12b in order to reinforce the workability and the graphite sheet.

  The graphite sheet 12a has, for example, a thickness of 10 μm and has anisotropy in the plane direction with respect to heat conduction.

  As the insulating sheet 12b, for example, a polyethylene terephthalate sheet or a polyimide sheet having a thickness of 10 μm (this thickness is easy to wind) is used, and the width is larger than the width of the graphite sheet. It protrudes about 5mm and protects the ear end. As the adhesive 12c, a hot melt adhesive or a styrene adhesive is used.

  As described above, the heat conduction path member has a thickness substantially increased by laminating a graphite sheet (including an insulating sheet) by winding it in a spiral tube shape a plurality of times. It can be expanded to reduce thermal resistance.

  Furthermore, since the anisotropic direction of the graphite sheet is made to coincide with the heat conducting direction (winding direction) as in the prior art, the thermal resistance in the heat conducting direction becomes smaller, and the heat conducting path member is moved from one connecting portion to the other. It is possible to effectively conduct heat to the connection part.

  In addition, when the heat conduction path member is repeatedly bent around the winding part, the bending stress generated by the bending can be dispersed throughout the winding part, thereby extending the life of the heat conduction path member.

  Further, the graphite sheet is reinforced by bonding an insulating sheet, and fatigue due to bending can be further reduced.

  Further, since the insulating sheet to be bonded has a width larger than that of the graphite sheet to protect the ear end portion of the graphite sheet, damage due to cracks generated from the ear end portion can also be prevented.

  FIG. 16 is a perspective view of the second embodiment of the heat conduction path member.

  The heat conduction path member 12 of this second embodiment, i.e., 12-2, uses a plurality (three are shown) of graphite sheets 12a, and the winding portion 13 is a cylindrical core 14 or Unlike the heat conduction path member 12-1 of the first embodiment, the connection portion 12 a-to the outside differs from the heat conduction path member 12-1 of the first embodiment in that it is wound around a cylindrical winding core 15 (the figure shows a cylindrical winding core (pipe)). 1 and the insulating sheet 12b are bonded together in the same manner as the heat conduction path member 12-1 of the first embodiment.

  Note that the plurality of graphite sheets 12a may be bonded together (by a hot melt adhesive or a styrene adhesive), or may be stacked without bonding.

  The material of the columnar or cylindrical cores 14 and 15 uses a resin material such as polyethylene, polyethylene terephthalate, polyimide, and ensures electrical insulation and heat insulation. The outer diameter of the cores 14 and 15 is about 5 mm, and the diameter of the hollow hole in the case of the cylindrical core (pipe) 15 is about 4 mm through which wiring can be inserted.

  The graphite sheet can be easily wound into a cylindrical shape by using a winding core, and in particular, a plurality of graphite sheets can be easily wound and the winding diameter dimension can be accurately suppressed, thereby preventing the shape from being deformed after being wound. Of course, the core may also be used in the heat conduction path member of the first embodiment.

  In addition, when a cylindrical winding core (pipe) is used, space can be saved through wiring or the like in the hollow hole of the winding core.

  Next, an example of the use of the heat conduction path member will be described with reference to a plan view of a personal computer housing incorporating FIG. 16 shown in FIG. 17 and a cross-sectional side view taken along line EE of FIG. 17 shown in FIG. In addition, the same code | symbol is attached | subjected to the same component as the conventional personal computer housing | casing of FIG.19 and FIG.20, and the description is abbreviate | omitted.

  One connecting portion 12a-1 extending from the winding portion 13 of the heat conduction path member 12 is formed on the heating element 24a (see FIG. 18) having the largest heat generation amount in the main body casing 24, that is, on the upper surface of the MPU. The heat spreader 10 made of a highly thermally conductive metal plate (for example, an aluminum plate or an alloy plate thereof) that receives and collects (collects) the generated heat is pressed with a pressing plate 16a and screwed.

  The other connecting portion 12a-1 is a heat radiating portion 101 (in FIG. 1) integrally formed by an in-mold method using a high thermal conductivity metal plate (for example, an aluminum plate or an alloy plate thereof) together with the display unit casing 100 as a base material. It is connected to one end of the heat conduction path portion 22 and the heat receiving portion 23) by screwing with the pressing plate 16b (or by bonding with a copper foil adhesive tape in the case of a base material that cannot be screwed). In addition, it is good to apply | coat a thermal compound to a connection surface.

  At that time, the winding axis of the winding part 13 of the heat conduction path member 12 is arranged so as to substantially coincide with the rotation center of the hinge part 37.

  As a result, the spiral winding diameter of the winding part accompanying opening and closing of the display unit casing expands and contracts and the bending stress is distributed over the entire winding part, so that the heat conduction path member accompanying opening and closing of the display unit casing Reduce fatigue.

  Next, in order to evaluate the heat dissipation effect of the case of this personal computer, the temperature was measured by actually operating the personal computer. In addition, the power consumption during the operation of the personal computer generates heat corresponding to each power with a printed wiring board 8.9 W (including 5 W of MPU), power supply 2.8 W, HDD 2.5 W, and PCMCIA 1.5 W. .

  In order to compare the heat radiation effect, a temperature measurement was performed by operating the personal computer provided with the above-described conventional heat radiation portion and the integrally formed heat conduction path portion as a comparative example.

  As a result, when connected by the heat conduction path member of the present invention, the temperature of the MPU is reduced by 10 ° C. compared to the comparative example, the surface temperature of the display unit case is lower than 40 ° C. A temperature reference of 45 ° C. or lower could be achieved, and a sufficient heat dissipation effect comparable to that of the comparative example could be confirmed.

  In addition, since the width of the polyethylene sheet, which is the insulating sheet of the heat conduction path member, is larger than the width of the graphite sheet, and the ear end portion of the graphite sheet is protected by the insulating sheet, the ear end portion is less likely to crack. .

  According to the repeated opening / closing evaluation of the display unit casing, it was confirmed that the heat conduction path member can withstand at least 20,000 times of opening / closing of the display unit casing.

  Next, although not shown in the figure, a heat conduction path member in which a winding portion is wound around a cylindrical core (a material is polyimide resin) is similarly incorporated into a personal computer, and an operation test was performed.

  As a result, the temperature of the MPU is reduced by 15 ° C. compared to the comparative example, the surface temperature of the display unit housing is lower than 40 ° C., and the temperature reference of 45 ° C. or less, which is the temperature standard of the PC housing surface, can be achieved. It was confirmed that the heat dissipation effect did not decrease even when the winding core was used.

  Moreover, by winding the winding part around the winding core, it was possible to prevent the winding shape of the graphite sheet from being broken, and to ensure the inner diameter dimension of the winding part with high accuracy.

  Further, the same heat radiation effect was obtained even with a heat conduction path member in which the winding portion was wound around a cylindrical winding core (pipe).

  Furthermore, since the wiring can be passed through the hollow hole of the cylindrical winding core, the internal space of the personal computer housing can be used effectively and space can be saved.

  Note that the heat conduction path member shown in FIGS. 14 and 16 is manufactured as a separate body (single unit) compared to the heat conduction path part and the heat receiving part that are integrally manufactured by the in-mold method together with the heat radiating part of the display unit casing. It becomes easy to provide the part.

  An electronic device housing that moves the heat inside the main body housing with a large calorific value to the heat radiating section of the display housing with a small calorific value without any trouble in opening and closing the display housing, and dissipates heat by natural convection to the outside A heat conduction path member used therefor can be provided.

Plan view of the first embodiment according to the present invention. BB sectional view of the heat dissipation part shown in FIG. The figure which shows the manufacturing process of the 2nd housing | casing of FIG. The figure which shows the manufacturing process following FIG. Top view of Fig. 1 built into a personal computer CC sectional view of FIG. The top view which shows the comparative example 1 with FIG. The top view of 3rd Example by this invention, and sectional drawing of a heat conduction path part Partial sectional view of the heat dissipation part of the fifth embodiment according to the present invention. Partial sectional view of the heat dissipation part of the sixth embodiment according to the present invention Partial sectional view of the heat dissipation part of the seventh embodiment according to the present invention The top view which shows the thermal radiation structure containing the rotation means of one Example by this invention FIG. 12 is an assembled side sectional view of the rotating means in FIG. 1 is a perspective view of a first embodiment of a heat conducting path member according to the present invention. FIG. FIG. 14 development view The perspective view of the 2nd Example of the heat conduction path member by this invention Plan view of a PC housing incorporating FIG. EE side sectional view of FIG. Plan view showing a conventional notebook computer AA sectional side view of FIG.

Explanation of symbols

10: Heat spreader 11: Display panel 12, 12-1, 12-2: Thermal conduction path member 12a: Graphite sheet 12a-1: Connection part 12b: Insulating sheet 12c: Adhesive 13: Winding part 14: Cylindrical winding Core 15: Cylindrical winding core (pipe)
16a, 16b: pressure plate 20, 40, 50, 60, 70, 80, 100: second housing (display housing)
21, 41, 51, 61, 71, 81, 101: heat radiation part 22, 42, 52: heat conduction path part 23, 43, 53: heat receiving part 24: first housing (main body housing)
24a: Heating element 25: Metal substrate 26: Resin 27: Side frame 28: Adhesive 29: Positioning hole 30: Mold for molding 30a: Lower mold 30b: Upper mold 31: Guide hole 32: Fixing pin 33: Coil spring 34: Runner 35: Stopper 36: Cavity 37: Hinge portion 56: PET sheet 65, 75, 85: First metal substrate 66: Resin 67, 76, 86: Second metal substrate 77: Adhesive 77a: Metal particles 78: Air layer 79: Air vent hole 87: Metal net 88: Coolant
89: Air venting hole 90: Rotating means 91: First heat pipe 91a: Pointed portion 92: Second heat pipe 93: Rotating body 93a: Hollow hole 93b: Conical hole 93c: Female thread portion 93d: Insertion hole 94 : Bearing 94a: Shaft hole 94b: Male thread portion 95: Fin 96: Thermally conductive fluid 97: O-ring 98: Liquid metal

Claims (3)

Winding in which a plurality of ends of a graphite sheet having anisotropy in the plane direction are connected to a member that generates heat, conducts heat or dissipates, and an insulating sheet is interposed on one or both sides of the graphite sheet. The heat conduction path member characterized by having a part. 2. The heat conduction path member according to claim 1, wherein the winding portion is wound around a columnar or cylindrical core. A first casing having a heating element; and a second casing having a heat radiating portion for radiating heat of the heating element of the first casing to the outside. In an electronic device housing that is opened and closed by a hinge portion with respect to one housing,
The heating element of the first casing and the heat radiating section of the second casing are connected by the connection portion of the heat conduction path member according to claim 1 or 2, and the winding section is wound around the winding section. An electronic device casing, wherein the rotation axis is disposed so as to substantially coincide with the rotation center of the hinge portion.

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