JP2007273868A - Heat sink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sink which has superior heat radiation characteristics and excellent manufacturability. <P>SOLUTION: The heat sink 1 has many fins 5 for heat radiation radially arrayed, and the fins 5 are provided on an outer peripheral surface of an annular body 4 while radially extending outward; and a shaft 3 for heat conduction is stood on a base 2 to which heat is conducted from outside and the annular body 4 is engaged with the shaft 3 in contact, so that the fins 5 are fitted to the annular body 4 to conduct heat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat sink in which a large number of fins for heat dissipation are arranged radially.

  As is well known, the heat sink is attached to the cooling object to increase the heat radiation area in order to promote the heat radiation from the cooling object. ) May be attached to the object to be cooled with good heat transfer. However, in order to have versatility, it is necessary to have a function of connecting the fins to the object to be cooled, so that the fin material is generally integrated with the base portion having an appropriate shape. Since the base part of the heat sink of this kind of configuration has no particular function in terms of heat dissipation, fins are attached to the entire surface of the base part in order to increase heat dissipation efficiency or heat dissipation capability as much as possible. It is common. An example of such a heat sink is described in Patent Document 1 and Patent Document 2.

  Conventionally, in order to improve the manufacturability of a heat sink in which fins are formed in a flat plate shape, a single metal plate is folded into ninety nines to form a fin, which is covered with the base so as to cover the entire surface of the base part. There is known a heat sink having a structure attached to a part. This type of fin is called a folded fin, and has a structure in which tunnel-like ventilation paths and ventilation paths opened upward are alternately formed, so that air is forced in the direction along the fin surface. And used as a heat sink for cooling. An example of this type of heat sink is described in Patent Document 3. Further, Patent Document 4 and Patent Document 5 describe examples of heat sinks configured to support radially arranged (formed) fins (heat sinks) and fans (heat radiating fans).

Japanese Patent Laid-Open No. 11-87961 Japanese Patent Laid-Open No. 2001-244677 US Pat. No. 6,288,899 US 2003/79861 US Patent No. 2003/63439

  As a heat sink having a structure in which a large number of fins are erected on the base portion as described in Patent Literature 1 and Patent Literature 2, there are a structure in which fins are attached to a base portion prepared in advance and a structure in which both are integrally molded. Are known. In the former structure in which the base part and the fin are separate members, it is necessary to join the two together to integrate them. However, if a means such as brazing or soldering is used as the structure for the joining, a thin plate shape With such fins, it is difficult to secure a sufficient bonding area, so it is difficult to reliably attach a thin plate-like fin capable of expanding the heat radiation area to the base portion with high strength.

  In order to eliminate such inconvenience, a structure in which a groove is formed in the base portion and the lower end portion of the thin plate-like fin is inserted into the groove and fixed can be considered. However, in such a structure, it is necessary to narrow the groove width as the fin is thinned. However, since the groove width that can be simultaneously formed when manufacturing the base portion is limited to a width that is larger than a certain degree, When a method such as cutting is employed to form a narrow groove, not only the number of processing steps is increased, but also the material yield is lowered and the productivity is lowered.

  In addition, as a method of manufacturing the fin and the base portion integrally, there are a casting method such as die casting and an extrusion molding method. In order to make the fin into a thin plate shape, a cavity for the fin or a molding die is used. Since the molten metal does not reach the inside of the cavity sufficiently, casting defects are likely to occur and the mold is easily damaged. To eliminate this, thicken the fins. Alternatively, it is necessary to reduce the height with respect to the wall thickness. As a result, inconveniences such as an increase in the heat capacity of the fins and the inability to secure a necessary and sufficient heat radiation area occur.

  On the other hand, in the heat sink using the folded fin, when the folded fin is joined to the base portion, it is joined at the folded edge of the folded fin, so it is difficult to secure the joining area. Since the bent edges are not aligned on a plane, a gap is created between one of the bent edges and the surface of the base portion. As a result, the thermal resistance between the two becomes large, and thus the heat dissipation characteristics are improved. May be reduced. Furthermore, when forced air cooling is performed by blowing air from above the heat sink, half of the space between the fins is in a tunnel shape, so it is necessary to open it upwards, and for that reason folded fins There is an inconvenience that requires additional processing such as cutting the bent edge.

  In the above-mentioned Patent Document 4 and Patent Document 5, since the heat sink, the fan, etc. are each fixed by means such as fitting or screwing, it becomes a factor of increasing the number of parts, and this is contrary to the recent downsizing. Resulting in. Therefore, the assembling property as a whole apparatus is inferior, and as a result, the manufacturability may be impaired.

  The present invention has been made against the background described above, and an object of the present invention is to provide a heat sink having excellent heat dissipation characteristics and good manufacturability.

  In order to achieve the above object, the invention of claim 1 is a heat sink in which a large number of fins for heat dissipation are arranged radially, and the fins extend radially outward on the outer peripheral surface of the annular body. In addition, a shaft portion for heat conduction is erected on a base portion to which heat is transmitted from the outside, and the annular body is closely fitted to the shaft portion so that the fin is the shaft portion or the annular shape. The heat sink is attached to a body so as to be capable of transferring heat.

  According to a second aspect of the present invention, the annular body according to the first aspect of the present invention is formed by bending a flat plate having the fins upright on one surface into a circular cross section so that the surface is on the outside. It is the heat sink characterized by being formed.

  Further, in the invention of claim 3, the annular body in the invention of claim 1 or 2 winds the flat plate body in which the fin is erected on one surface around the shaft portion so that the surface becomes the outside. It is attached to the said axial part by the heat sink characterized by the above-mentioned.

  As described above, according to the first aspect of the present invention, the fin is provided on the outer peripheral surface of the annular body so as to extend outward in the radial direction, and heat conduction is performed to the base portion to which heat is transmitted from the outside. A shaft portion is erected, an annular body is closely fitted to the shaft portion, and a fin is attached to the shaft portion or the annular body so that heat can be transferred. Therefore, when heat is transmitted from the outside to the base portion, the heat is conducted from the base portion to the shaft portion and is transmitted to each fin via the shaft portion or the annular body. Since these fins are arranged radially and are provided on the outer peripheral surface of the annular body so as to extend radially outward, the heat transmitted to the shaft portion or the annular body is diffused and radiated to each fin. be able to. Since each fin is directly exposed to the air flow, forced air cooling of the base portion is promoted, and the cooling efficiency is improved. Therefore, the heat of the base portion is efficiently transmitted to the fins by the shaft portion or the annular body and radiated. Moreover, when the cooling air from the outside enters between the fins, the air flow can collide with the fins to make the air flow turbulent. Therefore, heat exchange between the cooling air and the fins can be performed efficiently. As a result, since the heat dissipation of the fin can be improved, the cooling performance of the heat sink can be improved. Further, since the annular body is closely fitted to the shaft portion standing on the base portion, each fin can be securely fixed to the shaft portion. As a result, the heat sink can be easily assembled, and the heat sink productivity can be improved.

  Further, according to the invention of claim 2, since the annular body is formed by bending a flat plate body in which fins are erected on one surface into a circular cross section so that the surface is on the outside, Processing such as cutting is not required. Therefore, the heat sink can be manufactured with good manufacturing workability.

  Further, according to the invention of claim 3, since the annular body is attached to the shaft portion by winding a flat plate body having fins erected on one surface around the shaft portion so that the surface becomes the outside. Assembling property between the annular body and the shaft portion becomes good.

  The best mode for carrying out the present invention will be described below. As shown in FIGS. 1 to 3, a heat sink 1 as an example of the present invention has a base portion (clip portion) 2 to which heat is transmitted from the outside, and a shaft portion 3 for heat conduction is erected to form an annular body. A plurality of fins 5 for heat radiation are attached to the annular body 4 so that heat can be transferred. The fins 5 are arranged radially, and are provided on the outer peripheral surface (peripheral edge) of the annular body 4 so as to extend outward in the radial direction. Each fin 5 attached to the annular body 4 has a constant width on the outside as shown in FIGS. 4 and 5, but is configured such that the portion on the opposite side to the base portion becomes narrower as it approaches the center side. The entire fin is curved in the surface direction. Furthermore, the upper part 11 and the lower part 12 are bent at the outer peripheral part of the fin, and the upper parts or the lower parts are connected to each other. A part of each fin is connected to the upper part, and all fins are connected to the lower part. The shaft portion 3 is made of a metal having good thermal conductivity such as tough pitch copper (C1100), and is formed in a cylindrical shape.

  The base part 2 is attached to a heat exchange target portion of a heating element (such as an electronic component) (not shown) so that heat can be transferred. The base portion 2 is made of a metal having good thermal conductivity such as stainless steel (SUS) and is formed in a cross shape. A hole for inserting the shaft 3 is formed at the center of the base 2, and a plurality of (four) legs 7 are formed so as to extend in the radial direction from the hole. Furthermore, the hole part 8 in which fixing members, such as a volt | bolt and a pin, are inserted is formed in the front-end | tip part (flange part) of each leg part 7, respectively.

  An annular protrusion that protrudes in the radial direction and supports the lower end of the annular body 4 is formed at the lower end of the shaft 3. Moreover, the fin 5 is arrange | positioned facing the downward direction of the fan which is not shown in figure. A gap formed by the fins 5 is an air flow path, and the air flow path is formed by the fins 5 curved in the surface direction. Further, the inlet of the air flow path is formed by one end of the fin 5 and is arranged in the axial flow direction of the fan. On the other hand, the outlet of the air flow path is formed by the other end of the fin 5 and is disposed at right angles to the axial flow direction. The fin 5 is formed by bending a metal plate such as tough pitch copper (C1100), and is fixed to the annular body 4 with a bonding agent such as epoxy resin or solder. The bending angle of the fin 5 is about 15 to 20 degrees.

  Next, the operation of this heat sink will be described. First, heat generated in the heating element is transmitted to the base portion 2. The transmitted heat is conducted from the base portion 2 to the lower end portion of the shaft portion 3 having a temperature difference. The heat conducted to the lower end portion of the shaft portion 3 is transmitted from the shaft portion 3 to each fin 5 via the annular body 4. As described above, since the fins 5 are arranged radially and are provided on the outer peripheral surface of the annular body 4 so as to extend radially outward, the heat transmitted from the shaft portion 3 to the annular body 4 is each transmitted. It is possible to dissipate heat by diffusing to the fins 5.

  In this specific example, for forced cooling, air is sent from a fan (blower fan) (not shown) toward the heat sink 1. The cooling air sent by the fan enters the inside of the air flow path. At this time, the cooling air proceeds in the axial direction of the fan, and the air flow path has a curved shape. Therefore, the cooling air that has entered the air flow path has fins 5 (walls of the air flow path). Collide with. As described above, since heat is transferred from the annular body 4 to the fin 5, the temperature of the fin 5 is increased. As the temperature of the fin 5 and the cooling air collide with each other, a turbulent flow is generated inside the air flow path. Therefore, heat exchange is performed efficiently. On the other hand, since the shaft portion 3 is erected on the base portion 2 and the annular body 4 is closely fitted to the shaft portion 3, the heat conducted from the shaft portion 3 to the annular body 4 is transferred to each fin 5. Can diffuse and dissipate heat.

  Here, an example of a process for manufacturing the heat sink 1 will be briefly described. First, as shown in FIG. 6, a slit portion 15 is formed in advance at one end (both ends) of a flat plate (plate material) 14. A curved fin 5 is fixed to the surface 14A of the flat plate 14, and a bonding agent such as epoxy resin or solder is embedded in the slit portion 15. Next, the flat plate body 14 is bent into a circular cross section so that the surface 14A is on the outside, and is wound around the shaft portion 3. That is, both ends of the bent flat plate body 14 are bonded by the bonding agent described above, and attached to the shaft portion 3 as an annular body 4 as shown in FIG. Finally, the shaft portion 3 is attached to the base portion 2 to complete the heat sink 1.

  In the above example, the flat plate body 14 is bent into a circular cross section so that the surface 14A is on the outside, so that processing such as cutting is not required. Therefore, the heat sink can be manufactured with good manufacturing workability. Further, since the flat plate body 14 with the fins 5 standing on the surface 14A is wound around the shaft portion 3 so that the surface 14A is on the outer side, the assemblability of the annular body 4 and the shaft portion 3 is improved.

  In the specific example described above, the curved fins 5 are arranged on the surface of the annular body 4, but the heat sink of the present invention is not limited to this specific example. For example, the shaft portion and the annular body may be integrally formed, and a fin may be attached to the shaft portion so that heat can be transferred. Moreover, in this invention, an appropriate method can be used for each fixing method of a fin, an annular body, a flat plate, a base portion, a shaft portion, and the like. For example, the base portion and the shaft portion may be fixed by soldering or the like, or may be fixed by any other method.

It is a perspective view which shows one specific example of the heat sink in this invention. It is a top view which shows the heat sink of FIG. It is a side view which shows the heat sink of FIG. It is a top view which shows the fin in the heat sink of FIG. It is a side view which shows the fin in the heat sink of FIG. It is a figure explaining the manufacturing process of the heat sink in this invention. It is a figure which further demonstrates the manufacturing process of the heat sink in this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat sink, 2 ... Base part, 3 ... Shaft part, 4 ... Ring body, 5 ... Fin, 7 ... Leg part, 8 ... Hole part, 11 ... Outer peripheral part, 12 ... Upper part, 13 ... Lower part, 14 ... Flat plate body 14A ... surface, 15 ... slit part.

Claims (3)

A heat sink in which a large number of fins for heat dissipation are arranged radially,
The fin is provided on the outer peripheral surface of the annular body so as to extend outward in the radial direction, and a shaft portion for heat conduction is erected on a base portion to which heat is transmitted from the outside. A heat sink, wherein the fin is attached to the shaft portion so that heat can be transferred to the shaft portion or the annular body.   2. The annular body according to claim 1, wherein the annular body is formed by bending a flat plate body in which the fins are erected on one surface into a circular cross section so that the surface is on the outside. heatsink.   2. The annular body is attached to the shaft portion by winding a flat plate body having the fins erected on one surface around the shaft portion so that the surface is outside. Or the heat sink of 2.

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