JP2005158812A - Heat sink with fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heatsink with a fan for performing efficient cooling. <P>SOLUTION: In the heatsink with the fan, a plurality of plate-like fins 3 are arranged by leaving a prescribed interval, and gaps 8 are formed between the plate-like fins 3. Fans 6 blowing air to the gaps 8 by rotation of blades 7 are arranged opposite to the gaps 8. The plate-like fins 3 are tilted and arranged in such a way that the end of a circumference side is positioned on a front side rather than that of an internal circumference side in a rotation direction of the blade 7 against the normal direction of a circle where a rotation center of the blade 7 is set as a center. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat sink with a fan in which a plurality of plate-like fins are erected on a base portion in parallel with each other at a predetermined interval.

  In general, the heat sink has a function of expanding a substantial heat radiation area of the heat generating member or the high temperature part by contacting the heat generating member or the high temperature part. Therefore, in this type of heat sink, it is only necessary to provide as many fins as possible to form the heat radiation surface. However, in order to provide versatility to the object to be cooled, the structure in which the heat radiation fins are mounted on the base portion. Things are commonly used. Of the heat sinks having such a structure, the heat dissipating fins are formed in a flat plate shape, and one end portion thereof is integrated and assembled on one surface of the base portion so that the flat plate fins are parallel to each other. Heat sinks are known.

  According to this kind of heat sink, since the heat radiation area is enlarged, a large amount of heat can be dissipated, but in order to further increase the heat radiation amount, it is preferable to perform forced cooling to blow air toward the fins. In that case, cooling air will be sent into the gaps between the heat radiating fins, but considering the heat radiation efficiency of the heat sink as a whole and the freedom of mounting the blower, the tip side of the flat fin, that is, the flat fin A blower (fan) is disposed on the opposite side of the base portion from the side. As an example of the heat sink, there is known a structure in which an axial flow type fan is attached to an end portion on the side opposite to the base portion in the heat sink having the above structure. Therefore, in this heat sink with a fan, air outside the heat sink is sucked and blown into the gap between the flat fins by the axial fan, and forced cooling is performed. An example of such a heat sink is described in Patent Document 1.

In the heat sink having the above structure, the heat transmitted to the base portion is transmitted to the flat fins, and at the same time, cooling air is blown into the gaps of the flat fins by the axial flow fan. Then, the high-temperature air in the vicinity of the flat fin heated by the flat fin and the cooling air are heat-exchanged or replaced, and then the high-temperature air is blown out of the heat sink. Therefore, in the heat sink having the above structure, since the cooling air is exchanged in the gap between the flat fins, the amount of heat released from the flat fins increases, and as a result, the temperature rise from the heat generating member can be suppressed.
JP 2001-319998 A

  In the heat sink having the above structure, the axial flow type fan sends out air by rotating blades provided in the fan. Therefore, the air flow is spiral at the discharge part of the fan. On the other hand, since the flat fins are arranged in a certain direction, the flow direction of the air flow and the direction of the flat fins do not coincide with each other at any point. . As a result, in the said location, the air flow produced by the said axial flow type fan may not enter into the clearance gap between the said flat fins, and there exists a possibility that the heat radiation from the said flat fins may be inhibited. In other words, the cooling air cannot be sufficiently supplied between the plate-like fins arranged in parallel to each other, and there is a possibility that the heat dissipation capability becomes insufficient.

  The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a heat sink that has excellent heat dissipation capability and can be manufactured at low cost.

  In order to achieve the above object, the invention according to claim 1 is a shaft in which a plurality of flat fins are arranged at predetermined intervals, and air is blown into a gap formed by the flat fins by rotation of a blade. In the heat sink with a fan in which the flow-type fan is disposed to face the gap, the flat fins are more than the inner peripheral side end with respect to the normal direction of the circle around the rotation center of the blade. A heat sink with a fan, comprising a plurality of fins arranged so as to be inclined such that an outer peripheral side end portion is located on a front side in the rotation direction of the blade.

  Therefore, in the first aspect of the invention, the plurality of flat fins provided on the heat sink with a fan are arranged at a predetermined interval to form a gap. When cooling air is sent from the axial fan, the cooling air advances toward a gap formed by the flat fins of the heat sink while rotating spirally. Each flat fin is located on the front side in the rotational direction with respect to the normal direction of the circle centering on the rotational center of the blade of the axial fan, rather than the inner peripheral side end. Are arranged so as to be inclined. Therefore, the inlet of the gap is inclined in a direction parallel to the direction in which the cooling air flows. For this reason, the cooling air efficiently flows into the gap from the inlet.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the flat fin is arranged in parallel with a plane including the central axis of the blade.

  Therefore, in the invention of claim 2, since the flat fins are arranged in parallel with a plane including the central axis of the blade, the flat fins branched from the support portion are directed in one direction. Arranged. Therefore, an extrusion process can be employed for forming the heat sink.

  According to a third aspect of the invention, in addition to the configuration of the first or second aspect, a core portion is provided on the central axis of the blade, and the flat fins are provided in a radial direction with respect to the core portion. It is a heat sink with a fan characterized by having.

  Therefore, in the invention of claim 3, since the flat fins are arranged in a radial shape centering on the core portion, thermal diffusion is efficiently performed from the core portion to the flat fins. Therefore, heat dissipation from each flat fin is promoted, and the cooling efficiency of the heat sink is improved.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, a support portion extending radially outward from the core portion is provided, and the flat fins are arranged by branching from the support portion. This is a heat sink with a fan.

  Therefore, in the invention of claim 4, a support portion extending outward in the radial direction with the core portion as a center is provided, and the plate-like fins are arranged branched from the support portion. Therefore, the heat transmitted to the core part is efficiently transmitted from the support part to each flat fin. Therefore, heat exchange between the flat fins and the cooling air is promoted.

  According to a fifth aspect of the present invention, in addition to the configuration of the third or fourth aspect, the core portion is formed by inserting a plug portion into a hollow portion.

  Therefore, in the invention of claim 5, since the core portion is formed by fitting the plug portion into the hollow portion, the structure of the heat sink is simplified.

  According to a sixth aspect of the invention, in addition to the structure of any of the third to fifth aspects, a pedestal portion to which an electronic element is attached so as to be capable of transferring heat is provided at one end portion of the core portion. It is a heat sink with a fan.

  Therefore, in the invention of claim 6, since the electronic element is attached to the core portion so as to be able to exchange heat, the core portion has two functions of a base portion and a heat diffusion plate in a conventional heat sink. Therefore, the number of parts of the heat sink with a fan is reduced.

  According to a seventh aspect of the present invention, in addition to the configuration of the fifth or sixth aspect, the plug portion is a heat pipe.

  Therefore, in the invention of claim 7, since the plug portion is a heat pipe, heat is efficiently transmitted to each flat fin.

  According to the first aspect of the present invention, since the inlet of the gap is inclined in a direction parallel to the direction in which the cooling air flows, the cooling air is efficiently introduced from the inlet into the gap. The flow rate of the cooling air flowing through the gap can be increased. As a result, heat exchange between each flat fin and the cooling air can be performed efficiently, so that the cooling performance of the heat sink can be improved.

  According to the invention of claim 2, extrusion processing can be adopted for forming the heat sink. As a result, the manufacturing cost of the heat sink with a fan can be reduced.

  According to the invention of claim 3, when the air is blown from the axial flow fan to the flat fins, the heat transmitted to the core portion is diffused to the fins arranged in a radial shape. Can do. Therefore, when air is blown from the axial flow fan to the fins, heat can be efficiently radiated from each flat fin. As a result, the heat dissipation efficiency of the heat sink with a fan can be improved.

  Moreover, according to invention of Claim 4, heat exchange with the said flat fin and cooling air can be accelerated | stimulated. As a result, the heat dissipation characteristics of the heat sink as a whole can be improved.

  According to the invention of claim 5, the structure of the heat sink can be simplified, and the manufacturing cost of the heat sink with a fan can be further reduced.

  According to the invention of claim 6, the base portion can be omitted. As a result, the thermal resistance can be reduced. Moreover, since the number of parts can be reduced, the manufacturing cost of a heat sink with a fan can be reduced.

  According to the invention of claim 7, heat can be efficiently transferred to the flat fins. Therefore, the cooling performance of the heat sink with a fan can be improved.

  The best mode for carrying out the present invention will be described below. 1 to 3 show a heat sink 1 as an example of the present invention. The heat sink 1 includes a core part 2, a plurality of flat fins 3, a support part 4, and a pedestal part 5. The heat sink 1 has a structure in which an air flow is sent from a fan 6 to a gap formed by the flat fins 3 to dissipate heat. The fan 6 is a so-called axial fan that flows in the cooling air from the axial direction of the blade 7 (blade) and flows out in the axial direction. The central axis of the core portion 2 is disposed on the central axis of the blade 7.

  As shown in FIG. 2, in the heat sink 1, the support portions 4 are arranged in four directions around the core portion 2. In other words, the two support parts 4 intersect with each other at the center, and the core part 2 is disposed at the center. Therefore, the heat sink 1 is divided into four parts by the support part 4 with the core part 2 as the center. In this four-divided space, a plurality of plate-like fins 3 branched from each support portion 4 are arranged in parallel to each other in four directions with the core portion 2 as the center. Therefore, the plurality of flat fins 3 are arranged radially about the core portion 2. The plurality of support portions 4 and the plurality of flat fins 3 are made of a metal such as an aluminum alloy, for example, and are integrally formed by extrusion.

  On the other hand, the flat fins 3 arranged radially about the core portion 2 have an outer peripheral side end portion with respect to a normal direction of a circle centering on the axis of the fan 6 with respect to the inner peripheral side end portion. The blades 7 are arranged in an inclined manner so as to be positioned on the front side in the rotational direction. In other words, the flat fins 3 are arranged so as to be inclined in the rotation direction of the airflow from the fan 6. Further, since the arrangement direction of the flat fins 3 is divided into four directions, the inclination direction of the flat fins 3 with respect to the normal line is gradually reversed in the rotation direction of the blade 7. A gap 8 is formed in the heat sink 1 by the flat fins 3 arranged in this manner.

  The gap 8 opens at the upper end, the lower end, and the outer peripheral end of the heat sink 1. The upper end of the heat sink 1, in other words, the upper end portion of the plate-like fin 3 disposed to face the outlet of the fan 6 serves as the inlet 9 of the gap 8. Further, the lower end of the heat sink 1, that is, the lower end portion of the flat fin 3 serves as the outlet 10 of the gap 8. Further, the end portions of the flat fins 3 disposed around the heat sink 1 serve as the outlet 11 of the gap 8. Since the outflow port 11 is formed at the outer peripheral end of the heat sink 1, it is divided and arranged in four directions.

  The core portion 2 is formed by fitting a plug portion 13 into a cylindrical hollow portion 12 formed at the center portion of the heat sink 1. As shown in FIG. 3, the plug portion 13 is formed in a cylindrical shape with copper having good thermal conductivity. A pedestal 5 is formed at the lower end of the plug 13. The electronic element 14 is attached to the bottom of the pedestal portion 5 so as to be able to transfer heat. In addition, the core part 2 is not limited to column shape, You may form in other shapes.

  The operation of the heat sink 1 will be described. First, heat generated in the electronic element 14 is transmitted to the bottom of the core 2. The heat transferred to the core part 2 is conducted from the bottom of the core part 2 in the rising direction with a temperature difference. Then, heat is transmitted from the core part 2 to the support part 4, and further, heat is transferred from the support part 4 to each flat fin 3.

  On the other hand, air is sent from the fan 6 toward the heat sink 1 for forced cooling. The cooling air sent by the fan 6 advances toward the inlet 9 formed by the ends of the flat fins 3 of the heat sink 1 while rotating spirally. Each flat fin 3 is arranged to be inclined with respect to a normal line of a circle around the axis of the fan 6. Therefore, the inlet 9 is also inclined with respect to the normal. That is, the inflow port 9 is inclined in the direction in which the cooling air flows. Therefore, the inflow port 9 functions as a guide for guiding the cooling air to the inside of the gap 8, and the cooling air blown into the gap 8 flows smoothly and its flow rate increases.

  In addition, in the gap 8 between the plate-like fins 3 in which the direction of inclination with respect to the normal line of the circle centering on the axis of the fan 6 is opposite, the cooling air becomes a counterflow. For this reason, when the cooling air flows into the gap 8, it collides with the flat fins 3 to generate turbulent flow. Therefore, heat exchange between the cooling air and the flat fins 3 is promoted by the stirring effect due to the turbulent flow.

  Moreover, since each flat fin 3 is divided by the support part 4, cooling air is branched. The cooling air that has entered the gap 8 moves along the flat fins 3 that are the walls of the gap 8. Heat generated from the core portion 2 to a heating element such as an electronic element is transmitted to the flat fin 3. Therefore, the temperature of the flat fin 3 is increased. When the cooling air flows along the plate-shaped fin 3 that has been heated, heat exchange is performed between the cooling air and the plate-shaped fin 3.

  Thereafter, the cooling air further flows in the gap 8 along the plate-like fins 3 and is discharged from the outlet 10 and the outlet 11. Since the outlet 10 is an opening disposed at the lower end of the gap 8, a part of the cooling air linearly travels through the gap 8 and is discharged from the outlet 10. As a result, the resistance in the gap 8 is reduced and the flow of cooling air is promoted. On the other hand, the other cooling air collides with the surface of the core portion 2, proceeds along the flat fins 3 into the gap 8, and is discharged from the outlet 11.

  Further, the flat fins 3 are arranged radially around the core portion 2, and one end of the flat fin 3 is connected to the periphery of the core portion 2. Therefore, when the air is blown from the fan 6 to the flat fin 3, the heat transmitted to the core portion 2 is transmitted to the flat fin 3 and radiated. The heat transferred to the core portion 2 is diffused to each flat fin 3. Since each flat fin 3 is directly exposed to an air flow, forced air cooling of the heat sink 1 is promoted, and the cooling efficiency is improved. Therefore, the heat of the electronic element 14 is efficiently transmitted to the flat fins 3 by the core portion 2 and radiated.

  Further, a portion of the core portion 2 that is not exposed to the airflow is generated in a very narrow region facing the center of the fan 6. The core portion 2 is disposed in this portion and is connected to each flat fin 3. Therefore, since the other part is directly exposed to the air flow, forced air cooling of the core part 2 is promoted, and the cooling efficiency is improved. In addition, since a heating element such as the electronic element 14 can be attached to the back surface of the core part 2, the electronic element 14 and the plug part 13 are arranged close to each other. Therefore, the heat of the electronic element 14 is efficiently transmitted to the flat fins 3 by the core portion 2 and radiated.

  Further, the flat fins 3 are arranged radially around the core portion 2, and one end of the flat fin 3 is connected to the periphery of the core portion 2. Therefore, heat is transmitted to the core portion 2 when the air is blown from the fan 6 to the gap 8. The heat transferred to the core portion 2 is diffused to the flat fins 3 arranged in a radial shape. Since each flat fin 3 is directly exposed to an air flow, forced air cooling of the core part 2 is promoted, and the cooling efficiency is improved. Therefore, the heat of the core part 2 is efficiently transmitted to the flat fins 3 by the heat conducting member and radiated.

  Moreover, the core part 2 is replaced with the base part provided conventionally, and there is no part equivalent to the conventional base part. Therefore, thermal resistance is reduced.

  Further, since the flat fins 3 are arranged in parallel with the plane including the central axis of the blade 7, the flat fins 3 branched from the support portion 4 are formed in one direction. Therefore, an extrusion process can be adopted for forming the heat sink 1. As a result, the manufacturing cost of the heat sink 1 can be reduced. Moreover, thermal resistance can be reduced by the several flat fin 3 and the support part 4 being integrally processed by the extrusion process. Therefore, the cooling performance of the heat sink 1 can be improved.

  In the above-described specific example, the flat fin 3 is formed of an aluminum alloy, but the material of the flat fin 3 is not limited to the above-described aluminum alloy. For example, the flat fin 3 may be formed of copper.

  Moreover, in the above-mentioned specific example, although the plug part 13 has a solid structure with a copper member, the plug part of this invention is not limited to the above-mentioned structure. For example, the plug part may be formed of a heat pipe. In the heat sink 15 shown in FIG. 4, a columnar heat pipe 16 corresponding to the plug portion of the present invention is fitted in the hollow portion 12, and the electronic element 14 is attached to the bottom surface of the heat pipe 16 so that heat can be transferred. It is supposed to be.

  FIG. 5 shows the heat pipe 16. This heat pipe 16 encloses a condensable fluid such as water as a working fluid 18 in a state where a non-condensable gas such as air is deaerated inside a container (hollow sealed container) 17 sealed in an airtight state. Further, the heat conduction device is configured by providing a wick or the like (not shown) inside. The container 17 of the heat pipe 16 is formed in a cylindrical shape. A pedestal portion 5 is formed at the lower end of the container 17, and an electronic element 14 is attached to the pedestal portion 5 so as to be able to transfer heat.

  In the heat sink 15, the heat generated in the electronic element 14 is transmitted to the heat pipe 16. A portion where heat is transmitted to the heat pipe 16 is a heat input portion of the heat pipe 16. When heat is transferred to the heat input section, the working fluid 18 inside the container 17 evaporates, and the vapor moves above the heat pipe 16 having a low temperature and pressure. Therefore, the upper part of the heat pipe 16 is a heat radiating part. Since the upper part of the heat pipe 16 is connected to the end of each flat fin 3, heat is transmitted from the heat pipe 16 to each flat fin 3. And heat exchange with each flat fin 3 and the cooling air from the fan 6 is performed. On the other hand, the heat of the working fluid 18 is dissipated inside the heat radiating part to which heat has been transmitted, and the working fluid 18 is condensed and liquefied. Thereafter, the working fluid is refluxed to the heat input portion by capillary action or gravity, and is evaporated again by the heat of the electronic element 14.

  Therefore, in the heat sink 15, heat can be efficiently transferred to the flat fin 3 by the heat pipe 16. Therefore, the cooling performance of the heat sink 15 can be improved.

  6 and 7 show a heat sink 19 which is still another example of the present invention. The heat sink 19 includes the core portion 2, a plurality of flat fins 20, and the pedestal portion 5. The heat sink 19 has a structure in which an air flow is sent from the fan 6 to the gap formed by the flat fins 20 to radiate heat. In the example shown in FIGS. 6 and 7, the fan 6 and the heat sink 19 are fixed to the body by a fixing metal 21 provided between the plurality of flat fins 20. The fixing bracket 21 is formed of, for example, an aluminum member, and also functions as a heat radiating fin.

  On the other hand, the flat fins 20 arranged radially with the core portion 2 as the center have a curved shape. As a result, the outer peripheral end of the flat fin 20 is located on the front side in the rotational direction of the blade 7 with respect to the normal direction of the circle centered on the axis of the fan 6. Are arranged as follows. A gap 8 is formed in the heat sink 1 by the flat fins 20 arranged in this manner. The core portion 2 is formed by fitting a plug portion 13 into a cylindrical hollow portion 12 formed at the center of the heat sink 19.

  In the heat sink 19 described above, heat generated in the electronic element 14 is transmitted to the bottom of the core portion 2. The heat transferred to the core part 2 is conducted from the bottom of the core part 2 in the rising direction with a temperature difference. Then, heat moves from the core portion 2 to each flat fin 20.

  On the other hand, air is sent from the fan 6 toward the heat sink 19 for forced cooling. The cooling air sent by the fan 6 advances toward the inflow port 9 formed by the end portions of the flat fins 20 of the heat sink 1 while rotating spirally. Each of the flat fins 20 has a curved shape, and the outer peripheral end of the flat fin 20 rotates with respect to the normal direction of the circle centering on the axis of the fan 6. It is arranged so as to be located on the front side in the direction. Accordingly, the inlet 9 is inclined in the direction in which the cooling air flows.

  Therefore, the inflow port 9 functions as a guide for guiding the cooling air to the inside of the gap 8, and the cooling air blown into the gap 8 flows smoothly and its flow rate increases. Therefore, heat exchange can be efficiently performed by the cooling air and the flat fins 20. As a result, the cooling performance of the heat sink 19 can be improved.

  In the specific example described above, the flat fin 3 and the support portion 4 are integrally formed by extrusion, but the method of processing the heat sink 1 and the configuration of the members are not limited to the above. Therefore, for example, the heat sink 1 may be formed by a bending process and a die casting method.

It is a perspective view which shows one specific example of the heat sink of this invention. It is a top view of the heat sink of FIG. It is a side view of the heat sink of FIG. It is a longitudinal cross-sectional view which shows the other specific example of the heat sink of this invention. It is a longitudinal cross-sectional view which shows one specific example of the plug part of this invention. It is a perspective view which shows the other specific example of the heat sink of this invention. It is a top view of the heat sink of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,15,19 ... Heat sink, 2 ... Core part, 3,20 ... Flat plate fin, 4 ... Supporting part, 5 ... Base part, 6 ... Fan, 7 ... Blade, 8 ... Gap, 12 ... Hollow part, 13 ... plug part, 14 ... electronic element, 16 ... heat pipe.

Claims (7)

A plurality of flat fins are arranged at predetermined intervals, and an axial fan that blows air into a gap formed by the flat fins by rotation of a blade is provided with a fan that is disposed to face the gap. In the heat sink,
The flat fin is positioned such that the outer peripheral side end is located on the front side in the blade rotation direction with respect to the normal direction of the circle centered on the rotation center of the blade. A heat sink with a fan, comprising a plurality of fins arranged in an inclined manner.   The heat sink with a fan according to claim 1, wherein the flat fins are arranged in parallel with a plane including a central axis of the blade.   The heat sink with a fan according to claim 1, wherein a core portion is provided on a central axis of the blade, and the flat fins are provided in a radial direction with respect to the core portion.   The heat sink with a fan according to claim 3, wherein a support portion extending radially outward from the core portion is provided, and the flat fins are arranged so as to be branched from the support portion.   The heat sink with a fan according to claim 3 or 4, wherein the core portion is formed by fitting a plug portion into a hollow portion.   The heat sink with a fan according to any one of claims 3 to 5, wherein a pedestal portion to which an electronic element is attached so as to be able to exchange heat is provided at one end portion of the core portion.   The heat sink with a fan according to claim 5 or 6, wherein the plug portion is a heat pipe.

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