JP5896124B2 - heatsink - Google Patents

Description

  The present invention relates to a heat sink, and more particularly, to a heat sink with excellent heat dissipation efficiency formed by sheet metal processing.

  The heat sink suppresses the temperature rise of the electronic component that generates heat, and is attached so that the heat of the electronic component is efficiently transmitted, and is configured to dissipate the amount of heat generated by the electronic component.

  The main manufacturing methods of the heat sink include extrusion molding using a mold, die casting, sheet metal processing, and the like, and a material having high thermal conductivity is used.

  By the way, with recent downsizing, speeding up, and high functionality of electronic devices, the heat generation of electronic components mounted on the devices has increased, and a heat dissipation structure with high heat dissipation efficiency is required for many electronic components. ing.

  In order to dissipate heat with optimal efficiency in a limited space for a wide variety of electronic components that require a heat dissipation structure, a heat dissipation structure tailored to individual electronic components or multiple electronic components is required. An optimal heat dissipation structure that matches the internal structure is also required.

  In view of this, the heat sink is often developed as a dedicated product specialized for each electronic component or each electronic device in order to obtain an optimum heat dissipation structure.

  FIG. 6 is a configuration explanatory view showing an example of a conventional heat sink. In FIG. 6, a plurality of electronic components 11 to 18 having different heights are mounted on the printed wiring board 10.

  The heat sink 20 is a metal material having good thermal conductivity, for example, aluminum, integrated as an extruded member, and a plurality of fins 21 are formed in parallel at equal intervals on the upper surface, and the printed wiring board 10 is formed on the lower surface. A plurality of stepped portions 22 to 27 each having a size and a height are formed so as to be in thermal contact with one of the electronic components 11 to 18 or a plurality of adjacent electronic components mounted on Yes. Specifically, the electronic components 11 to 13 correspond to the step portions 22 to 24, the electronic components 14 and 15 correspond to the step portion 25, the electronic component 16 corresponds to the step portion 26, and the electronic components 17 and 18 It is formed by cutting so as to correspond to the stepped portion 27.

  FIG. 7 is a structural explanatory view showing another example of a conventional heat sink, and the same reference numerals are given to the portions common to FIG. In FIG. 7, a plurality of electronic components 11 to 18 having different heights are mounted on the printed wiring board 10 as in FIG. 6.

  Each of the heat sinks 30 to 70 is formed by bending a metal plate having good thermal conductivity, for example, an aluminum plate into a bottomed rectangular tube shape. Specifically, the bottom surface of the heat sink 30 is in thermal contact with the top surface of the electronic component 11, the heat sink 40 is in thermal contact with the top surfaces of the electronic components 12 and 13 having the same height, and the heat sink 50 is The bottom surface thereof is in thermal contact with the upper surfaces of the electronic components 14 and 15 having the same height, the heat sink 60 is in thermal contact with the upper surface of the electronic component 16, and the heat sink 70 is an electron having the same bottom surface in height. It is bent so as to be in thermal contact with the upper surfaces of the parts 17 and 18.

  6 and 7, the heat contact surfaces between the electronic components 11 to 18 mounted on the printed wiring board 10 and the heat sinks 20 to 70 are provided with, for example, heat conduction in order to improve heat transfer efficiency. For example, silicon grease or the like is applied or a heat conductive sheet is disposed.

  FIG. 8 is also a configuration explanatory view showing another example of a conventional heat sink, and shows a heat dissipation structure described in Patent Document 1. FIG. In FIG. 8, a heat radiating sheet metal 83 for radiating heat from the IC 82 on the substrate 81 and a heat radiating sheet 84 interposed between the IC 82 and the heat radiating sheet metal 83 are provided.

  FIG. 9 is an assembly view of FIG. In FIG. 9, the heat radiation sheet 84 is disposed between the IC 82 on the substrate 81 and the heat radiating metal plate 83 so that the substrate 81 and the heat radiating metal plate 83 are opposed to each other, and the substrate 81 and the heat radiating metal plate 83 are brought close to a predetermined distance. By fixing the relationship, the state of FIG. 8 is formed.

  The protrusion 83a of the heat radiating metal plate 83 secures contact between the heat radiating metal plate 83 and the heat radiating sheet 84 in spite of the variation in the thickness of the heat radiating sheet 84 in the positional relationship of FIG. Has a shape, size, number and arrangement so as not to cause In FIG. 8, two protrusions 83a having a shape obtained by cutting a part of a spherical surface with a flat surface or a dome shape and having an appropriate size are arranged at two appropriate locations.

JP 2010-129954 A

  However, depending on the internal structure of the printed wiring board 10 or the electronic device in which the printed wiring board 10 is incorporated, the configuration of FIG. 6 may require complicated cutting and additional machining of the lower surface of the heat sink 20, which is expensive. turn into.

  In addition, for mass-produced products, it is possible to produce a dedicated heat sink that is optimally designed using a dedicated mold for extrusion molding and die casting, considering the investment in the mold. Although it is sufficiently inexpensive, it is difficult to recover the investment in the mold in the case of a small-volume product.

  On the other hand, according to the configuration of FIG. 7, when the electronic components 11 to 18 have different heights, a plurality of heat sinks 30 to 70 corresponding to the heights must be provided.

  In addition, due to the problem of mounting space, there is a limit to increasing the contact area between the electronic components 11 to 18 and the heat sinks 30 to 70 by a bending structure, and sufficient heat radiation efficiency cannot be obtained in many cases.

  Further, according to the configuration of FIG. 8, in order to efficiently transfer the heat of the IC 82 to the heat radiating sheet metal 83 through the heat radiating sheet 84, the protrusion 83 a is provided on the heat radiating sheet metal 83, and the protrusion 83 a is brought into contact with the heat radiating sheet 84. However, a specific configuration for efficiently radiating the heat transmitted to the heat radiating metal plate 83 as in the present invention is not shown.

  The present invention solves these problems, and an object of the present invention is to provide a heat sink having a high heat radiation efficiency suitable for each electronic component or each electronic device at a low cost by a sheet metal structure.

In order to achieve such a problem, the invention according to claim 1 of the present invention is:
In a heat sink using a metal heat sink attached so as to be in thermal contact with the upper surface of a heat generating electronic component mounted on a printed wiring board,
The region excluding the heat generating electronic component region is drawn so that a frustoconical top surface protrudes from the contact surface with the upper surface of the heat generating electronic component to the other surface, and a screw is inserted in the approximate center of the top surface. A first metal heat radiating plate formed with a plurality of first protrusions of the same shape provided with holes;
A plurality of first screw holes are provided so as to be in contact with the top surfaces of the first protrusions, and are screwed into screws inserted from the insertion holes of the first protrusions. A second metal heat radiating plate in which a plurality of second protrusions having the same shape as the first protrusions are formed in the same direction as the first protrusions in a region that does not overlap with the protrusions of
It is characterized by including.

The invention of claim 2 is the heat sink according to claim 1,
The first metal heat radiating plate and the second metal heat radiating plate are formed by cutting out and bending from a single metal plate into a predetermined shape.

The invention of claim 3 is the heat sink according to claim 1 or 2,
A heat dissipation sheet is interposed between the upper surface of the heat generating electronic component and the first metal heat radiating plate, and a plurality of through holes are formed in a contact region of the first metal heat radiating plate with the upper surface of the heat generating electronic component. Is provided.

The invention of claim 4 is the heat sink according to claim 3,
The thickness of the heat dissipation sheet is selected according to the height of the heat generating electronic component such that the height including the heat dissipation sheet is equal.

  As a result, the surface area per space can be increased as compared with a heat sink having a conventional sheet metal structure, and the interruption of the air flow to the heat radiating surface can be reduced, so that the heat radiation efficiency can be improved.

It is composition explanatory drawing which shows the specific example of the heat sink based on this invention. FIG. 2 is an assembly diagram of FIG. 1. Structure explanatory drawing of the 1st metal heat sink 210 which comprises this invention It is composition explanatory drawing which shows the other Example of this invention. It is manufacturing process explanatory drawing of FIG. It is structure explanatory drawing which shows an example of the conventional heat sink. It is composition explanatory drawing which shows the other example of the conventional heat sink. It is composition explanatory drawing which shows the other example of the conventional heat sink. It is an assembly drawing of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a structural explanatory view showing a specific example of a heat sink according to the present invention, where (a) is a plan view and (b) is a front view. FIG. 2 is an assembly view of FIG.

  1 and 2, a heat-generating electronic component 101 such as an IC is mounted on a printed wiring board 100, for example. On the upper surface of the heat generating electronic component 101, three metal heat sinks 210, 220, 230 formed in a predetermined shape, sequentially stacked, screwed, and integrated as a heat sink, It is attached so as to be in thermal contact with the upper surface of the component 101.

  These three metal heatsinks 210, 220, and 230 that constitute the heat sink are provided with through holes, projections by drawing, screw holes, ventilation holes, etc. according to the respective lamination positions by sheet metal processing. Yes.

  3A and 3B are explanatory views of the configuration of the first metal heat radiating plate 210 located in the lowermost layer of the heat sink to be laminated. FIG. 3A is a side view and FIG. 3B is a bottom view. In FIG. 3, a substantially central portion of the metal heat radiating plate 210 is an electronic component region 211 that faces the upper surface of the heat generating electronic component 101 mounted on the printed wiring board 100. The electronic component area 211 is provided with a plurality of through holes 212 (five in this embodiment).

  These through holes 212 are provided in the printed wiring board 100 when the heat sink sheet 300 is interposed between the upper surface of the heat generating electronic component 101 and the metal heat sink 210 when attaching the laminated heat sink to the printed wiring board 100. It has a function of appropriately absorbing and dispersing and relaxing adjustment so that an excessive pressing force is not applied as a load.

  In attaching the heat sink laminated with the heat dissipation sheet 300 interposed between the upper surface of the heat generating electronic component 101 and the metal heat dissipation plate 210 to the printed wiring board 100, the heat dissipation sheet 300 is reliably compressed by compressing in the thickness direction. The contact is maintained and the thermal resistance of the heat dissipation sheet 300 is lowered.

  However, if the pressing force when compressing the heat dissipation sheet 300 in the thickness direction is too strong, an excessive load is applied to the printed wiring board 100, and the printed wiring board 100 is deformed and connected to electronic components that are mounted. There is a possibility that the solder may be peeled off or the printed wiring board 100 may be broken.

  However, if the through hole 212 is provided in the electronic component region 211, a part of the heat radiating sheet 300 is pushed out to the through hole 212 according to the pressing force when the heat radiating sheet 300 is compressed in the thickness direction. A part of the load applied to the wiring board 100 can be substantially absorbed and dispersed.

  Therefore, by selecting a heat dissipation sheet 300 having a thickness that makes the pressing force to the printed wiring board 100 slightly stronger, and appropriately adjusting and setting the area of the through hole 212, an appropriate pressing force on the printed wiring board 100 can be obtained. Thus, reliable thermal contact and reduction of the thermal resistance of the heat dissipation sheet 300 can be realized.

  In addition, since the surface area of the through holes 212 is increased as the hole diameter is smaller due to the thickness of the through holes 212 and the metal heat sink 210, the through holes 212 are provided with a plurality of holes having a smaller area. It is effective.

  Further, a case where a plurality of heat-generating electronic components having different heights as shown in FIGS. 6 and 7 are cooled with a single heat sink according to the present invention is also conceivable. At this time, it is not impossible to select a heat-dissipating sheet 300 having a predetermined thickness that is the same height for each heat generating electronic component, but the thickness of the commercially available heat-dissipating sheet 300 is generally 0.5 mm. Therefore, it is practically difficult to adjust the load on the printed wiring board 100 only by selecting the thickness of the heat dissipation sheet 300.

  Also in this case, the heat dissipation sheet 300 can be selected for each heat-generating electronic component with a thickness that increases the pressing force against the printed wiring board 100, and can be adjusted by the through hole 212 to reduce the pressing force.

  In the vicinity of the top, bottom, left, and right of the electronic component region 211, a plurality of protrusions 213 having the same shape that are drawn so that a frustoconical top surface protrudes from the contact surface with the top surface of the heat generating electronic component to the other surface ( In the present embodiment, four) are formed, and a screw insertion hole 214 is provided at substantially the center of the top surface of these protrusions 213.

  Furthermore, a plurality of vent holes 215 (four in this embodiment) are formed at intersections of virtual parallel lines passing through the centers of the upper, lower, left and right projections 213. The diameters of these vent holes 215 are formed such that the heads of fixing screws for passing the third metal heat sink 230 on the second metal heat sink 220 and fixing them with screws can pass through. Has been.

  In FIGS. 1 and 2 again, the insertion holes 214 of the protrusions 213 are inserted into the second metal heat dissipation plate 220 that is laminated so as to contact the top surface of the protrusions 213 provided on the first metal heat dissipation plate 210. Four screw holes 221 that are screwed into screws inserted from the first metal heat sink 210 are provided, and these protrusions are formed in the electronic component region 211 and the vent hole 215 that do not overlap with the protrusions 213 provided in the first metal heat sink 210. A plurality of projections 222 (five in the present embodiment) having the same shape as the portion 213 are formed in the same direction as the projections 213, and screw insertion holes 223 are provided at substantially the center of the top surfaces of the projections 222. ing.

  In the state where the second metal heat sink 220 is laminated so as to contact the top surface of the protrusion 213 provided on the first metal heat sink 210, it faces the printed wiring board 100 of the first metal heat sink 210. The screw 216 is inserted into the insertion hole 214 of the protrusion 213 from the surface, and is screwed into the screw hole 221 provided in the second metal heat radiating plate 220. Thereby, the second metal heat sink 220 is laminated and fixed to the first metal heat sink 210.

  The third metal heat radiating plate 230 laminated so as to be in contact with the top surface of the protrusion 222 provided on the second metal heat radiating plate 220 laminated and fixed to the first metal heat radiating plate 210 has a protrusion 222. 5 screw holes 231 that are screwed into screws inserted from the insertion holes 223, and a region that does not overlap the protrusion 222 provided in the second metal heat sink 220, that is, the first metal heat sink 210. A plurality of protrusions 232 (four in this embodiment) having the same shape as those of the protrusions 222 are formed in the same direction as the protrusions 222 in the same region as the protrusions 222. Insertion hole 233 is provided.

  In the state where the third metal heat sink 230 is laminated so as to contact the top surface of the protrusion 222 provided on the second metal heat sink 220, the second metal heat sink 220 faces the printed wiring board 100. From the surface, a screw 225 is inserted into the insertion hole 224 of the protrusion 223 so as to pass through the vent hole 215 provided in the first metal heat radiating plate 210, and the screw hole provided in the third metal heat radiating plate 230. 231 and screw. As a result, the third metal heat sink 230 is laminated and fixed to the second metal heat sink 220.

  In this way, the three metal heat sinks 210, 220, 230 are laminated and fixed and integrated as a heat sink as shown in FIG. 1, and a mounting screw (not shown) is inserted into a mounting hole (not shown) provided in the heat sink. The heat-dissipating electronic component 101 mounted on the printed wiring board 100 is attached via a heat dissipation sheet 300 so as to be in thermal contact with the upper surface.

  According to the heat sink according to the present invention, the metal heat radiation plates 210, 220, 230 are provided with a plurality of protrusions 213, 222, 232 drawn into a truncated cone shape, so as shown in FIGS. Compared to a conventional heat sink having a sheet metal structure, the surface area per space can be increased, and the air flow to the heat radiating surface is hardly blocked, so that the heat radiation efficiency is improved.

  In addition, the sheet metal structure as shown in FIG. 6 does not require cutting, and most of the manufacturing process can be formed by NC turret punch press such as drawing or punching. It can be suppressed relatively inexpensively.

  Furthermore, since the die used for drawing can be diverted from a dish punching die used to immerse the head of the screw with a housing cover of an electronic device, the initial investment can be suppressed.

  In the above embodiment, the example in which the three metal heat sinks 210, 220, and 230 are laminated and fixed to be integrated as a heat sink has been described. However, the number of metal heat sinks that are stacked and fixed is not limited to three. More than one sheet may be laminated and fixed, and at least two metal heat dissipating plates 210 and 220 may be stacked and fixed, so that higher heat radiation efficiency can be obtained as compared with the structure of only one sheet shown in FIG.

  Further, when the heat dissipation sheet 300 is not provided between the upper surface of the heat generating electronic component 101 and the heat sink, the plurality of through holes 212 in the electronic component region 211 of the first metal heat dissipation plate 210 may be omitted. If these through holes 212 are provided, the heat radiation effect by the inner wall portion of the through holes 212 can also be expected.

  FIG. 4 is a structural explanatory view showing another embodiment of the present invention, and FIG. 5 is a view of cutting and bending the heat sink of FIG. 4 from a single metal plate into a predetermined shape by an NC turret punch press. It is process explanatory drawing to manufacture, Comprising: The same code | symbol is attached | subjected to the part which is common in FIG.1 and FIG.2.

  As shown in FIGS. 4 and 5, one metal plate 200 cut into a predetermined shape is sequentially bent in a predetermined direction, so that three metal heat radiating plates are formed as in FIGS. A substantially rectangular parallelepiped heat sink in which 210, 220, and 230 are sequentially stacked and fixed can be realized.

  FIG. 5A shows a plate shape of one metal plate 200. In general, the first metal heat sink 210 at the center, the second metal heat sink 220 on the left side of the first metal heat sink 210, and the third metal heat sink on the right side of the first metal heat sink 210. Three regions of 230 are cut out, and each metal heat sink 210, 220, 230 is provided with the same through-hole as in FIGS. 1 and 2, a projection by screwing, a screw hole, a vent hole, and the like. However, a specific description thereof will be omitted.

  Further, as shown in FIG. 4, the metal heat sinks 210, 220, and 230 are bent sides 217, 225, 226, 234, and 235 that are bent at substantially right angles along the stacking direction with respect to the respective main planes. This area is also provided. These bent sides 217, 225, 226, 234, and 235 are provided in order to expand the heat radiation area as a heat sink. These bent sides 217, 225, 226, 234, and 235 are provided with a large number of through holes as shown in the bent side 217, for example, in order to further expand the heat radiation area as necessary.

  FIG. 5B shows a state in which the portion of the first metal heat radiating plate 210 is bent at a substantially right angle leaving the height of the bent side 217.

  FIG. 5 (c) shows a state in which the portion of the second metal heat radiating plate 220 is bent at a substantially right angle in the same direction as the portion of the first metal heat radiating plate 210, leaving the height of the bent sides 225 and 226. Show.

  FIG. 5D shows a portion of the third metal heat sink 230 with a portion of the first metal heat sink 210 and a portion of the second metal heat sink 220 leaving the height of the bent sides 234 and 235. It shows a state where it is bent almost at right angles in the same direction.

  FIG. 5E shows a state in which the portion of the second metal heat radiating plate 220 is bent substantially at a right angle in the counterclockwise direction with respect to the bent side 217. In this state, the portion of the second metal heat radiating plate 220 is laminated on the portion of the first metal heat radiating plate 210.

  FIG. 5 (f) shows a state in which the portion of the third metal heat radiating plate 230 is bent substantially at right angles to the bent side 217 in the clockwise direction.

  As a result, the third metal radiator plate 230 is laminated on the second metal radiator plate 220, and the three metal radiator plates 210, 220, 230 as shown in FIG. An almost rectangular parallelepiped heat sink can be realized.

  In the example of FIGS. 4 and 5, the main plane of the third metal heat sink 230 is flat and the hole is drilled. However, the first metal heat sink 210 and the second metal heat sink 220 Protruding portions by similar drawing processing may be provided, or a plurality of kerfs or slits may be provided to increase the heat radiation area.

  As described above, according to the present invention, even with a small amount, a heat sink having a sheet metal structure with excellent heat dissipation efficiency suitable for individual electronic components or individual electronic devices can be provided at low cost.

DESCRIPTION OF SYMBOLS 100 Printed wiring board 101 Heat generating electronic component 200 Metal plate 210 1st metal heat sink 211 Electronic component area 212 Through-hole 213 Protrusion part (drawing process)
214 Screw insertion hole 215 Vent hole 216 Screw 217 Bending side 220 Second metal heat sink 221 Screw hole 222 Projection (drawing)
223 Screw insertion hole 224 Screw 225, 226 Bending side 230 Third metal heat sink 231 Screw hole 232 Projection (drawing)
233 Screw insertion hole 234, 235 Bending side 300 Heat dissipation sheet

Claims (4)

In a heat sink using a metal heat sink attached so as to be in thermal contact with the upper surface of a heat generating electronic component mounted on a printed wiring board,
The region excluding the heat generating electronic component region is drawn so that a frustoconical top surface protrudes from the contact surface with the upper surface of the heat generating electronic component to the other surface, and a screw is inserted in the approximate center of the top surface. A first metal heat radiating plate formed with a plurality of first protrusions of the same shape provided with holes;
A plurality of first screw holes are provided so as to be in contact with the top surfaces of the first protrusions, and are screwed into screws inserted from the insertion holes of the first protrusions. A second metal heat radiating plate in which a plurality of second protrusions having the same shape as the first protrusions are formed in the same direction as the first protrusions in a region that does not overlap with the protrusions of
A heat sink characterized by including.   2. The heat sink according to claim 1, wherein the first metal heat radiating plate and the second metal heat radiating plate are cut out from a single metal plate into a predetermined shape and bent.   A heat dissipation sheet is interposed between the upper surface of the heat generating electronic component and the first metal heat radiating plate, and a plurality of through holes are formed in a contact region of the first metal heat radiating plate with the upper surface of the heat generating electronic component. The heat sink according to claim 1, wherein the heat sink is provided.   The heat sink according to claim 3, wherein the thickness of the heat dissipation sheet is selected according to the height of the heat generating electronic component so that the height including the heat dissipation sheet is equal.

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