JP2012169529A - Radiator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiator capable of improving heat radiation efficiency (thermal conductivity) as compared with the conventional one and reducing the weight.
SOLUTION: A plurality of carbon fiber bodies 1 made of carbon fiber paper are used. Each carbon fiber body 1 has a pair of carbon fiber papers 2 and 3 having a flat surface and a pair having a flat surface. A corrugated structure having an air flow passage 5 provided with a carbon fiber paper 4 having a corrugated surface sandwiched between carbon fiber papers 2 and 3, one of the plurality of carbon fiber bodies 1. Is used as a base part, and the other carbon fiber bodies 1 are joined as perpendicular to the carbon fiber body used as the base part and used as fin parts, and each of the carbon fiber bodies 1 is an air flow passage having a corrugated structure. 5 are arranged and joined so as to be in the same direction.
[Selection] Figure 7

Description

  The present invention relates to a radiator.

  In recent years, the power consumption of semiconductors has increased at an accelerating rate, and the amount of heat generated has increased accordingly, increasing the demand for higher performance cooling systems. The power consumed by high-density integrated circuits has increased, and at the same time as the amount of heat generated, the heat generation density has also increased rapidly. With the forced heat absorption by the conventional Peltier element and the forced air cooling structure with the heat sink and the fan, the cooling capacity has begun to reach its limit, and examples of adopting a liquid cooling system with higher cooling capacity have also appeared.

  Also in the LED, which is an optical semiconductor, with the improvement in brightness, the path from the conventional display application to the illumination application is on the path of increasing power. The biggest problem with LED elements is that even if the light emission efficiency is improved, most of the electric power that is input still becomes heat, and the brightness and life are reduced by the heat generated by itself.

  In particular, in a high-power LED, a package / heat dissipation structure that can receive heat of several watts per chip is required, and metal core substrates and ceramic substrates excellent in thermal conductivity have been put into practical use. In particular, ceramic substrates are attracting attention for two main reasons: improved thermal conductivity due to advances in material technology, and the fact that an insulating layer is not required unlike a metal core substrate because it is an insulating substrate. .

  Further, as a matter demanded simultaneously with the improvement of the heat radiation performance, there is a weight reduction of the heat radiation member. The current high-power LED products are mostly made up of heat by a heat sink. Although measures such as reducing the heat sink volume have been taken by actively using the product casing as a heat dissipation path, the demand for the heat sink will not disappear. By reducing the weight of the heat sink, the weight of the product is reduced, which improves the ease of handling, and is expected to lead to an improvement in fuel consumption especially in moving bodies such as automobiles.

  In order to suppress the increase in weight and increase the heat dissipation capability, it is desirable to have a structure with a large surface area. For example, Patent Literature 1 and Patent Literature 2 show a heat exchange device and a heat radiating body having a corrugated structure (also referred to as a honeycomb structure or a cardboard structure).

  That is, in Patent Document 1, as shown in FIG. 1, a core of a heat exchange device 107 is formed from at least one heat transfer tube 101 and a core body 104 provided on the outer periphery of the heat transfer tube 101, and the heat transfer tube 101 and a core body 104 are formed of a resin material, and a technique is shown in which a plurality of fluid flow passages 106 are provided in the core body 104 in a direction orthogonal to the tube axis of the heat transfer tube 101 to form a corrugated core. ing.

  Further, in Patent Document 2, as shown in FIG. 2, a positive temperature coefficient thermistor 201 in which electrodes are formed on both main planes and arranged adjacent to each other or an aluminum plate 202a having a plate thickness changed at equal intervals. 202b is bent into a corrugated shape so that the thicker portion 202a becomes the top of one side, and the heat dissipating body 202 is formed by brazing an aluminum thin plate 202c on each top, and the positive temperature coefficient thermistor 201 is formed. A positive temperature coefficient thermistor heating element is shown in which the top portion 202a side of the heat dissipating body 202 having a large thickness is fixed to both main planes.

  As described above, the corrugated structure is widely used as a heat dissipation structure such as an air filter and a radiator, and a heat exchanger structure such as an air heater, and is a general structure in which strength is ensured.

  Further, carbon materials are attracting attention as light weight and good heat conduction materials. For example, Patent Document 3 discloses a radiator using an expanded graphite sheet. That is, Patent Document 3 shows a radiator having a heat radiation sheet portion 304 in which carbon fibers 303 are interposed together with a carbonized adhesive layer 302 between expanded graphite sheets 301 as shown in FIG. In FIG. 3, reference numeral 305 denotes a heat radiation columnar part, reference numeral 306 denotes a heat conductive layer, and M denotes a heating element.

JP 2005-042771 A Japanese Patent No. 30633395 Japanese Patent Laid-Open No. 2000-091453

  However, in the heat exchange device of Patent Document 1, since the entire structure including the corrugated structure is formed of a resin material, the thermal conductivity is poor, and when applied to a small heat source, only the vicinity of the heat source becomes high temperature and heat dissipation. It is difficult to sufficiently transfer heat to the end of the vessel. In Patent Document 1, it is described that carbon fibers are mixed in a resin as a measure for improving the thermal conductivity. There was a problem that the high thermal conductivity that is an advantage of the carbon fiber was interrupted at the boundary with the resin.

  Further, although the heat dissipating body 202 of Patent Document 2 has a corrugated structure, since the material thereof is aluminum, it is necessary to increase the thickness in order to increase the heat dissipation efficiency, which increases the weight and reduces the weight. There was a problem that it was not suitable.

  Moreover, in the heat radiator of patent document 3, since it is the structure which laminates many expansion | swelling graphite sheets and handles as a single plate, it has a surface area small compared with a corrugated structure, and heat exchange performance and intensity | strength (flexibility) are inferior. There was a problem.

  An object of this invention is to provide the heat radiator which can improve heat dissipation efficiency (thermal conductivity) compared with the past, and can achieve weight reduction.

  In order to achieve the above object, the invention according to claim 1 uses a plurality of carbon fiber bodies formed of carbon fiber paper, and each of the carbon fiber bodies includes a pair of carbon fiber papers having flat surfaces. And a corrugated structure having an air flow passage provided with a carbon fiber paper having a corrugated surface sandwiched between a pair of carbon fiber papers having a flat surface, and one of the plurality of carbon fiber bodies. The sheet is used as a base part, and the other carbon fiber bodies are used as fin parts joined perpendicularly to the carbon fiber body used as the base part, and each carbon fiber body has a corrugated air flow passage. It is characterized by being arranged and joined in the same direction.

  The invention according to claim 2 is the radiator according to claim 1, wherein the carbon fiber paper forming each carbon fiber body has a fiber orientation of 30 ° to 45 with respect to the cut edge portion of the carbon fiber paper. It is characterized by being cut so as to have an angle range of °.

  The invention according to claim 3 is the radiator according to claim 1 or 2, wherein the radiator has an air flow path of the corrugated structure of each of the carbon fiber bodies parallel to the air convection direction. It is characterized by being installed in.

  According to the first to third aspects of the present invention, a plurality of carbon fiber bodies formed of carbon fiber paper are used, and each carbon fiber body includes a pair of carbon fiber papers having a flat surface and a flat surface. A corrugated structure having an air flow passage provided with a corrugated carbon fiber paper sandwiched between a pair of carbon fiber papers having a smooth surface, and one of the plurality of carbon fiber bodies is The carbon fiber body is used as a base part, and the other carbon fiber bodies are joined vertically to the carbon fiber body used as the base part to be used as fin parts, and each carbon fiber body has the same air flow path of the corrugated structure. Since they are arranged and bonded so as to face each other, the heat radiation efficiency (thermal conductivity) can be remarkably improved and a sufficient weight reduction can be achieved as compared with the conventional case.

  In particular, according to the invention described in claim 2, in the radiator according to claim 1, in the carbon fiber paper forming each of the carbon fiber bodies, the fiber orientation is 30 ° with respect to the cut edge portion of the carbon fiber paper. Since it cut | judges so that it may become the thing of an angle range of -45 degrees, the heat radiator which has practically sufficient material strength can be provided.

It is a figure which shows the heat exchange apparatus of patent document 1. It is a figure which shows the heat radiator of patent document 2. FIG. It is a figure which shows the heat radiator of patent document 3. FIG. It is a disassembled perspective view of the carbon fiber body of the corrugated structure of this invention. It is a figure which shows the carbon fiber body of the corrugated structure of this invention. It is a figure which shows the optimal orientation of carbon fiber. It is a perspective view which shows the structural example of the heat radiator of this invention. It is a top view which shows the structural example of the heat radiator of this invention. It is a figure which shows the heat sink (radiator) of the Example of this invention. It is a figure which shows the heat sink (radiator) of a comparative example. It is a figure which shows the modification of this invention. It is a figure which shows the modification of this invention. It is a figure which shows the modification of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In order to solve the above-mentioned problems of the prior art, the inventor of the present application pays attention to a carbon fiber having both strength and flexibility and having high thermal conductivity as a constituent material of a radiator, and completed the present invention. It was.

  That is, the present invention is made by adhering a carbon fiber paper formed by knitting vertically and horizontally without chopping the carbon fiber into a corrugated structure with the orientation of the carbon fiber aligned. The first gist is to form one carbon fiber body.

  Next, the second gist of the present invention is to form a heat sink having a T shape or an E shape by using a plurality of carbon fiber bodies having such a corrugated structure. That is, one of a plurality of carbon fiber bodies is used for mounting a heat source and for heat diffusion (that is, used as a base portion), and at least one other carbon fiber body is used as a base portion. The second gist is to use a T-shaped or E-shaped heat sink fin portion by bonding to a carbon fiber body used as a base portion so as to be perpendicular to the heat source mounting surface of the body. To do. At this time, each of the carbon fiber bodies of the corrugated structure is preferably arranged so that the air flow passage of the corrugated structure is parallel to the wind (natural convection or forced convection) passing through the entire heat sink. .

In other words, the present invention uses a plurality of carbon fiber bodies formed of carbon fiber paper, and each carbon fiber body has a pair of carbon fiber papers having a flat surface and a pair of carbon fiber papers having a flat surface. It has a corrugated structure having an air flow passage provided with carbon fiber paper having a corrugated surface sandwiched between carbon fiber papers, and one of the plurality of carbon fiber bodies is used as a base part, The other carbon fiber bodies are used as fins by being joined perpendicularly to the carbon fiber body used as the base part, and the carbon fiber bodies are arranged so that the air flow passages of the corrugated structure are in the same direction. It is characterized by being joined.

  Furthermore, in this invention, the carbon fiber paper which forms each carbon fiber body is cut | judged so that the orientation of a fiber may become a thing of an angle range of 30 degrees-45 degrees with respect to the cutting edge part of carbon fiber paper. Is preferable from the viewpoint of strength.

  In the present invention, the radiator is preferably installed so that the air flow passage of the corrugated structure of each carbon fiber body is parallel to the air convection direction (the direction of natural convection or the direction of forced convection). .

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 4 is an exploded perspective view of a carbon fiber body having a corrugated structure according to the present invention, and FIG. 5 is a view showing a carbon fiber body having a corrugated structure according to the present invention. 4 and 5, the corrugated structure carbon fiber body 1 of the present invention includes a pair of carbon fiber papers 2 and 3 having a flat surface and a pair of carbon fiber papers 2 and 3 having a flat surface. It is composed of three carbon fiber papers with carbon fiber papers 4 having corrugated surfaces sandwiched between them. In FIG. 5, reference numeral 5 denotes an air flow passage (corrugated structure air flow passage) formed between a pair of carbon fiber papers 2 and 3 having flat surfaces and a carbon fiber paper 4 having corrugated surfaces. is there. In order to assemble (finish) the three carbon fiber papers 2, 3, and 4 as shown in FIG. 4 as the carbon fiber body 1 having a corrugated structure as shown in FIG. 5, the carbon fiber paper 4 having a corrugated surface is used. Is preferably bonded with a heat conductive adhesive (not shown) so as to be sandwiched between the pair of carbon fiber papers 2 and 3 from above and below.

  Here, as the carbon fiber papers 2, 3, and 4, commercially available materials such as carbolite (trade name), trading card (trade name), pyrofil (trade name), etc. can be used as appropriate. From this point of view, it is desirable to use one having a thermal conductivity in the fiber direction of 500 W / mK or more. In Examples described later, carbon fiber paper having a thermal conductivity in the fiber direction of 800 W / mK and a thickness of 200 μm was used.

  The three carbon fiber papers 2, 3 and 4 constituting the corrugated carbon fiber body 1 have the same orientation of the carbon fibers of at least three carbon fiber papers 2, 3 and 4, respectively. good. From the viewpoint of material strength, as shown in FIG. 6, each carbon fiber paper 2, 3, 4 has a fiber orientation D with respect to the cut edge of carbon fiber paper (one side outside carbon fiber paper) EG. It is preferably cut so as to have an angle range θ of about 30 ° to 45 °. FIG. 4 shows the optimal fiber orientation direction D of each carbon fiber paper 2, 3, and 4.

  Moreover, various things, such as silicone RTV rubber (brand name), can be used for a heat conductive adhesive. As the heat conductive adhesive, those having a heat conductivity of 2 W / mK or more are suitable.

  Referring to FIG. 5, the thickness T of the carbon fiber body 1 is, for example, about 3 mm, and the pitch (corrugated pitch) P of the corrugated structure of the carbon fiber body 1 is, for example, about 5, 2 mm.

  7 and 8 are a perspective view and a top view showing a configuration example of the radiator of the present invention. 7 and 8, the radiator of the present invention uses a plurality of carbon fiber bodies 1 formed of carbon fiber paper as described above, and one of the plurality of carbon fiber bodies 1 is The other carbon fiber bodies used as the base portion 1a are vertically joined to the carbon fiber body 1a used as the base portion and used as fin portions 1b, 1c, 1d, 1e, 1f, 1g, 1h, The fiber bodies 1a, 1b, 1c, 1d, 1e, 1f, 1g, and 1h are arranged and joined so that the airflow passages 5 of the corrugated structure are in the same direction. In addition, the heat conductive adhesive mentioned above can be used also for joining each carbon fiber body 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h.

  The carbon fiber body 1a used as the base portion and the carbon fiber bodies 1b, 1c, 1d, 1e, 1f, 1g, and 1h used as the fin portions are joined at the locations indicated by reference numeral MT in FIGS. In this way (that is, like the joining portion of the carbon fiber body 1a and the carbon fiber body 1c), the carbon fiber paper 4 having the corrugated surface of the carbon fiber body 1a is in a position where it contacts the carbon fiber paper 3 on the fin side. The carbon fiber paper 4 having corrugated surfaces of the carbon fiber bodies 1b, 1c, 1d, 1e, 1f, 1g, and 1h used as the fin portions is preferably joined. That is, in the examples of FIGS. 7 and 8, the carbon fiber body satisfying this joining condition is 1c, and the other carbon fiber bodies 1b, 1d, 1e, 1f, 1g, and 1h are deviated from the joining conditions. Although the case where the carbon fiber body 1a is joined at the position is shown, the other carbon fiber bodies 1b, 1d, 1e, 1f, 1g, and 1h are also carbon fibers having a corrugated surface of the carbon fiber body 1a. It is preferable that the carbon fiber paper 4 having corrugated surfaces of the other carbon fiber bodies 1b, 1d, 1e, 1f, 1g, and 1h is bonded to the position where the paper 4 is in contact with the carbon fiber paper 3 on the fin side.

  Further, as shown in FIG. 7, the radiator of the present invention has a longitudinal direction Y of each carbon fiber body 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h (air flow in the air flow passage 5 of the corrugated structure). It is preferable to install and use such that the (direction) is a vertical direction (direction of gravity) Z with respect to the ground or floor. That is, the longitudinal direction Y of each carbon fiber body 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h (the air flow direction of the air flow passage 5 of the corrugated structure) is perpendicular to the ground or the floor ( (Direction of gravity) When installed so as to be Z, the direction Y (= Z) of the air flow passage 5 of the corrugated structure is parallel to the air convection direction (the direction of natural convection when no fan or the like is used), About both a base part and a fin part, heat dissipation efficiency can be raised significantly by the convection of the air in the airflow path 5 of a corrugated structure.

(Example)
The inventor of the present application assumes a heat sink applied to a high-power LED (1 mm square chip size, 5 mm square LED package), for example, as a heat source, and is used as a base portion as shown in FIG. The carbon fiber body 1a has a size in which the length in the vertical direction Y is 50 mm and the length in the horizontal direction X is 60 mm, and each carbon fiber body 1b, 1c, 1d, 1e, 1f, 1g, 1h used as a fin portion. A heat sink (heat radiator) having a height H of 30 mm was produced as an example of the present invention.

  Specifically, the heat sink (heat radiator) according to the example of the present invention was manufactured as follows.

That is, first, the carbon fiber paper was cut out as follows.
A piece: 50 mm × 60 mm 2 pieces B piece: 50 mm × 80 mm 1 piece C piece: 50 mm × 30 mm 14 pieces D piece: 50 mm × 40 mm 7 pieces

  Next, as shown in FIG. 4, the B piece is bent so that the side having a length of 80 mm has a corrugated cross section (the height L of the corrugation is 2.6 mm). Then, the carbon fiber body 1 (1a) having a corrugated structure of finished dimensions: 50 mm long × 60 mm wide × 3 mm thick was prepared as shown in FIG.

  Similarly, corrugated structure with a total of 7 finished dimensions: 50 mm long x 30 mm wide x 3 mm thick, with a combination of 2 C pieces and 1 D piece (40 mm long side corrugated) Carbon fiber body 1 (1b, 1c, 1d, 1e, 1f, 1g, 1h) was prepared. At this time, the inside of the corrugated structure of both AB and CD penetrates the space in the longitudinal direction Y (that is, the air flow passage 5 of the corrugated structure penetrates in the longitudinal direction Y, respectively).

  The corrugated carbon fiber body 1 (1a) made of AB serves as a base portion, and the corrugated carbon fiber body 1 (1b, 1c, 1d, 1e, 1f, 1g, 1h) made of CD serves as a fin portion. Such a heat sink structure, that is, a heat sink structure in which the base portion as shown in FIGS. 7 and 8 is 50 mm long × 60 mm wide and the height H of the fin portion is 30 mm was formed by a heat conductive adhesive. The longitudinal direction Y is the same as the direction in which the spaces (corrugated structure air flow passages 5) of the carbon fiber bodies 1a, 1b, 1c, 1d, 1e, 1f, 1g, and 1h of each corrugated structure pass.

(Comparative example)
In order to compare with the heat sink (heat radiator) of the Example of this invention, the heat sink (heat radiator) used as a comparative example was prepared.

  FIG. 10 is a view showing a heat sink (heat radiator) as a comparative example. A heat sink (heat radiator) as a comparative example is a black anodized heat sink that is a general prior art and has the same external dimensions as the heat sink (heat radiator) of the embodiment of the present invention. That is, in a heat sink (heat radiator) as a comparative example, A6063 (thermal conductivity 200 W / mK) is used for the aluminum material, the dimensions of the base portion 51 a are 50 mm long × 60 mm wide × 3 mm thick, and the fin portions 51b, 51c, The height H of 51d, 51e, 51f, 51g, 51h is 30 mm, which is the same outer dimension as the heat sink (heat radiator) of the embodiment of the present invention. The fin portions 51b, 51c, 51d, 51e, 51f, 51g, and 51h have a thickness of 1 mm, and the surface is black anodized (emissivity 0.9).

(Verification experiment)
About each of the heat sink (heat radiator) of the Example of this invention prepared as mentioned above and the heat sink (heat radiator) used as a comparative example, a 5 mm square LED package 10 (a heat source) is formed in the center of the base portions 1a and 51a. The wiring is not shown) (see FIGS. 9 and 10), and heat conduction can be ignored so that the longitudinal direction Y of the heat sink is perpendicular to the ground or floor surface (direction of gravity) Z It was suspended in the air with a thread (not shown).

  In this state, 5 W of electric power was applied to the LED package 10, and the heat dissipation capability in the natural air cooling state was compared.

As a result, the temperature of the LED package 10 is 58.2 ° C. Example:
Comparative example: 59.1 ° C
Thus, the example was better.
The weight of the heat sink alone is: Example: 14.4 g (specific gravity 1.8)
Comparative example: 52.6 g (specific gravity 2.7)
Thus, the embodiment could achieve a sufficient weight reduction.

  This is considered to be because in the heat sink (heat radiator) of the embodiment of the present invention, the corrugated structure having the air flow passage 5 was used, so that the wind passed through the fins and the effective heat exchange area was expanded. . Further, since carbon fiber paper is lighter than aluminum, the weight can be reduced sufficiently to about one third of that of the comparative example.

  Thus, according to the present invention, it is possible to provide a lightweight radiator (heat sink) adapted to a small heat source such as an LED by taking advantage of the carbon fiber having high thermal conductivity.

  That is, in order to efficiently dissipate heat from a small heat source such as an LED, a total of two functional parts are required, a part that diffuses heat and a part that releases heat to the air. Furthermore, it is very preferable from the viewpoint of mass productivity that the whole can be made of the same highly heat-conductive material and can be manufactured with a single easy construction method and with a practically sufficient strength (with flexibility). The present invention also has such conditions.

  As shown in FIG. 11, the heat radiator of the present invention can be further provided with a fan 7 in the configuration of FIG. In this case, by setting the direction of the wind by the fan 7 to the direction of the air flow passage 5 of the corrugated structure (longitudinal direction Y), the heat dissipation efficiency can be further enhanced by forced convection of air.

  Moreover, about the heat radiator (heat sink) of this invention, the magnitude | size can be made into arbitrary desired sizes, and the whole shape can be made into arbitrary desired things. For example, in the above example, the fin portions 1b, 1c, 1d, 1e, 1f, 1g, and 1h are rectangular, but the fin portions 1b, 1c, 1d, 1e, 1f, 1g, and 1h are used. For example, a trapezoidal shape as shown in FIG. 12 or a triangular shape as shown in FIG. In addition, the base portion 1a is also rectangular in the above example, but may be in the shape of an ellipse, for example, in accordance with the intended use and place of use.

  In the above example, the heat source is an LED. However, even when the heat source is other than an LED, heat can be radiated using the radiator (heat sink) of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used for lighting devices such as automobile lighting, projectors, and general lighting, and devices and devices that require heat dissipation such as electronic devices.

DESCRIPTION OF SYMBOLS 1 Corrugated carbon fiber body 2, 3, 4 Carbon fiber paper 5 Air flow path 7 Fan 10 LED package

Claims (3)

A plurality of carbon fiber bodies formed of carbon fiber paper are used, and each of the carbon fiber bodies is a waveform sandwiched between a pair of carbon fiber papers having a flat surface and a pair of carbon fiber papers having a flat surface. And a corrugated structure having an air flow passage provided with carbon fiber paper having a surface of one of the plurality of carbon fiber bodies is used as a base portion, and the other carbon fiber bodies are The carbon fiber body used as a base part is vertically joined to be used as a fin part, and the carbon fiber bodies are arranged and joined so that the airflow passages of the corrugated structure are respectively in the same direction. And a radiator. 2. The radiator according to claim 1, wherein the carbon fiber paper forming each of the carbon fiber bodies has a fiber orientation in an angle range of 30 ° to 45 ° with respect to the cut edge portion of the carbon fiber paper. A radiator characterized by being cut. The heat radiator according to claim 1 or 2, wherein the heat radiator is installed so that an air flow passage of a corrugated structure of each carbon fiber body is parallel to a convection direction of air. vessel.

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