JP2008066641A - Electronic apparatus and heatsink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus which suppresses the discharge of electromagnetic waves to the outside by using a heatsink preventing a fin assembly from becoming a source of discharge of the electromagnetic waves. <P>SOLUTION: The heatsink is built in a casing 100, and the electronic apparatus is constituted. The heatsink is constituted of the fin assembly 110 which is constituted by arranging a plurality of plate-like fins each having a plurality of protrusions formed in the same direction and connecting the tip of each of the plurality of protrusions of each fin with adjacent other fins and where the plurality of protrusions are connected in parallel with one another among the fins, a heat-receiving plate 120 which receives heat from the electronic apparatus that is an object of cooling, and heat pipes 131 and 132. Since the protrusions are connected in parallel among the fins, the impedance of the fin assembly 110 is made small, and the emission of the electromagnetic waves is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electronic apparatus including a heat sink for cooling an electronic component that can generate heat during operation, such as a processor, and more particularly to a structure of a fin assembly that serves as a heat radiating portion of the heat sink.

The heat sink attached to the electronic component generally has a fin assembly in which a large number of fins are assembled so that the heat radiating portion has a large surface area and can easily diffuse heat.
Most conventional fin assemblies have a plurality of plate-like fins arranged in parallel with a predetermined interval. Each fin is electrically connected by the support | pillar which has electroconductivity.

In a heat sink having a fin assembly in which a large number of fins are arranged, the impedance of the fins increases as the distance from the ground plane such as a substrate increases. This may cause an impedance difference between the fin that is electrically closest to the ground plane and the fin that is farthest away, thereby creating a potential difference between the fins. This potential difference generates a high-frequency current in the heat sink and radiates electromagnetic waves.
The conventional heat sink has no idea to solve the problem that the fin assembly itself becomes an electromagnetic wave emission source only from the viewpoint of improving thermal radiation efficiency.

  An object of the present invention is to provide an electronic device that suppresses the emission of electromagnetic waves to the outside and a heat sink that prevents an electromagnetic wave from being emitted.

  In a fin assembly having a structure in which a plurality of plate-like fins are arranged, a potential difference occurs due to a difference in impedance for each fin. Due to this potential difference, a high-frequency current flows through the fin assembly. By this high frequency current, electromagnetic waves are radiated from the fin assembly. In particular, when the frequency of the high-frequency current matches the resonance frequency of the fin, the emission of electromagnetic waves increases. If the radiation of electromagnetic waves from the fin assembly can be reduced by reducing the difference in impedance between the fins, the radiation of electromagnetic waves can be limited.

  Based on the above considerations, the present invention provides a housing for mounting an electronic device capable of generating heat, a heat receiving medium that absorbs heat generated by the electronic device mounted on the housing, and the housing There is provided an electronic device including a heat sink provided at a predetermined portion of the heat sink and a heat transfer medium that guides heat absorbed by the heat receiving medium to the heat sink. In this electronic device, the heat sink is configured by arranging a plurality of plate-like fins in which a plurality of protrusions are formed in the same direction, and the plurality of protrusions of each fin are joined to other adjacent fins. The plurality of protrusions are electrically connected in parallel between the fins. Since the fins constituting the heat sink have a plurality of protrusions electrically connected in parallel between adjacent fins, the difference in impedance between the fins can be reduced. Therefore, the radiation of electromagnetic waves from the heat sink can be reduced. From the viewpoint of enhancing the cooling effect, it may further include a fan for releasing heat transmitted to the heat sink from the fins to the outside of the casing.

  The present invention also provides a heat sink suitable for specifications in electronic devices and the like. The heat sink of the present invention is a heat sink for dissipating heat generated in an object that can generate heat, and a plurality of plate-like fins in which a plurality of protrusions are formed in the same direction are arranged. The plurality of protrusions are joined to other adjacent fins, and a fin assembly is provided in which the plurality of protrusions are electrically connected in parallel between the fins. In the fins constituting the fin assembly, a plurality of protrusions are electrically connected in parallel between adjacent fins, so that the impedance difference between the fins can be reduced. Therefore, the radiation of electromagnetic waves from the fin assembly can be reduced to limit the radiation of electromagnetic waves.

  The protrusion used for such a heat sink can be used by joining another piece to the plate-like portion of the fin, but it is bent starting from one side of a plurality of rectangular cutouts provided in the fin. Thus, it is possible to easily form a protrusion that is integral with the fin. In this case, when a hollow cylindrical column having a cross-sectional shape matched to the shape of the hole formed by bending the notch is fitted into the hole, the fins are strongly coupled. In addition, since the pillars are fitted into the holes, detailed positioning of the fins is not necessary when the fins are joined.

  The fin may include a locking portion for locking a protrusion of another fin. For example, when the locking portion has a concave portion, a protruding portion that matches the shape of the concave portion is formed at the tip of the protrusion, and this protruding portion is used as the concave portion of the other fin. Press fit. When the locking portion has a convex portion provided on the fin in a direction opposite to the protrusion, the tip of the protrusion is locked to the convex portion of the other fin. The By providing such a locking part, the joining state of the protrusions becomes good, and the impedance due to the contact of the protrusions can be reduced. The locking portion is provided, for example, at the base end portion of the protrusion.

  For example, when the protrusion is formed longer than the distance from the fin to which the length from the base end to the tip is combined, the protrusion is joined so as to bias the other fin away. Alternatively, the protrusions are joined so as to partially overlap the protrusions of the other fins. In these cases, the protrusions are strongly pressed against other fins, or the contact area of the other fins with the protrusions is increased, so that the impedance due to the contact of the protrusions can be reduced. When the length from the base end to the tip end of the plurality of protrusions formed on one fin is constant, the plurality of fins are arranged in parallel to each other.

  The fins may be formed in a flat plate shape, but may be formed in a wave plate shape or a plate shape having a triangular cross section. In such a fin, since the heat radiation area is increased, the heat radiation efficiency is improved.

  When the fins are arranged so that the distance between at least one pair of fins constituting the fin assembly is not uniform, the protrusions formed on at least one fin of the pair of fins from the base end to the tip end The length may be a length corresponding to the distance between the pair of fins. For example, the length from the base end to the tip of the protrusion formed on the one fin is formed with a length corresponding to the distance between the pair of fins for each protrusion. Moreover, the length from a base end to a front end may be formed with a length corresponding to the pair of fins with a single protrusion.

  In another embodiment of the heat sink of the present invention, the heat sink further includes a heat receiving medium that absorbs heat generated in the object to be cooled, and a heat transfer medium that guides the heat absorbed by the heat receiving medium to any one of the walls. Shall.

  In the electronic device of the present invention, the fins of the heat sink are connected to the other fins at more portions than in the conventional case by the protrusions, so that the difference in impedance between the fins is reduced and it is difficult to generate a potential difference. Therefore, the emission of electromagnetic waves from the heat sink is suppressed.

Embodiments of a heat sink to which the present invention is applied will be described below with reference to the drawings.
As shown in FIG. 1, the heat sink of this embodiment absorbs heat generated by an object to be cooled, for example, an electronic component (not shown) in contact with the object to be cooled and the fin assembly 10 that functions as a heat radiating unit. A heat receiving plate 20 and a heat pipe 30 connected to the fin assembly 10 and the heat receiving plate 20 are provided. The heat receiving plate 20 may be in contact with an electronic component and directly absorb heat generated in the electronic component, or may absorb heat generated in the vicinity from the vicinity of the electronic component. . Note that the fin assembly 10 may be brought into contact with the electronic component, or the fin assembly 10 may be disposed near the electronic component to absorb heat generated around the electronic component.

  The fin assembly 10 is configured by arranging a plurality of fins 11 inside a frame body 13. As shown in FIG. 1, the heat sink of this embodiment cools an object to be cooled by transmitting heat generated by the object to be cooled from the heat receiving plate 20 to the fin assembly 10 through a heat pipe 30.

The fin assembly 10 has a structure as shown in FIG. 2, for example. That is, the fin assembly 10 is arranged with the fins 11 made of a flat metal plate having a plurality of protrusions 12 in the same direction one by one as illustrated. In FIG. 2, the protrusion 12 is formed by bending a plurality of rectangular cutouts provided in the fin 11 starting from one side. Each fin 11 is joined to the plate-like portion of the fin 11 adjacent to the tip portion of the protrusion 12. The joining may be performed with a conductive adhesive, or may be performed by pressure bonding, welding, or other means. A hollow cylindrical column 14 is fitted into a hole 12a of each fin 11 formed by forming the protrusion 12. The support | pillar 14 is connected to the hollow heat pipe 30, for example. With such a configuration, the plurality of fins 11 are arranged so that the plate-like portions are parallel to each other. In principle, the fins 11 are all metal plates having the same shape and size, but this is not always the case, and some of the fins 11 may be metal plates having the same shape and size.
A plurality of fins 11 having such a structure are accommodated in the frame body 13, thereby forming the fin assembly 10. The protrusion 12 may be formed by bending a notch from the fin 11 and joining a plate-like piece different from the fin 11 to the plate-like portion of the fin 11.

  The protrusion 12 has a structure as shown in FIGS. 3a to 3c, for example. In FIG. 3 a and FIG. 3 b, a protrusion 12 b is formed at the tip of the protrusion 12 and is locked to the plate-like portion of the other fin 11. In FIG. 3 a, a triangular protrusion 12 b is formed at the tip of the protrusion 12. In FIG. 3 b, a rectangular protrusion 12 b is formed at the tip of the protrusion 12. In addition, a locking portion 12c, which is a hole for locking the protruding portion 12b, is provided at the base end of the protrusion 12 so as to match the shape of the protruding portion 12b. In FIG. 3a, since the shape of the protruding portion 12b is a triangle, the shape of the locking portion 12c is also formed by a triangular hole in the plate 12 of the protrusion 12 and the fin 11, respectively. In FIG. 3b, since the shape of the protruding portion 12b is rectangular, the shape of the locking portion 12c is also formed by a rectangular hole in the protrusion 12 and the plate-like portion of the fin 11, respectively. 3a and 3b show an example in which the locking portion 12c is formed as a hole, but the locking portion 12c only needs to be a recess that can lock the protruding portion 12b.

  The protrusion 12 in FIG. 3 c does not have the protrusion 12 b as shown in FIGS. 3 a and 3 b, but a locking portion 12 d that protrudes in the direction opposite to the protrusion 12 is provided at the base end of the protrusion 12. Have. The locking portion 12d is provided with a notch extending in a direction opposite to the notch for the protrusion 12 on one side which is a starting point where the protrusion 12 is bent, and the protrusion 12 is formed when the protrusion 12 is formed. It is formed by bending in the opposite direction. Such a locking portion 12d may be a convex portion protruding in the opposite direction to the protrusion 112. The tip of the other protrusion 12 is locked to the locking portion 12d.

  The protrusion 12 is coupled to the plate-like portion of the fin 11 as shown in FIGS. 4a and 4b or FIGS. 5a and 5b, for example. FIG. 4A is a diagram for explaining a bonding state of the fin 11 on which the protrusion 12 as shown in FIG. 3B is formed. The protruding portion 12 b of the protrusion 12 is press-fitted into the locking portion 12 c formed on the other fin 11. The protruding portion 12b is joined to the locking portion 12c by a conductive adhesive, crimping, welding, or other means. FIG. 4B is a view for explaining the bonding state of the fin 11 on which the protrusion 12 as shown in FIG. 3C is formed. The tip of the protrusion 12 is locked to a locking portion 12 d formed on the other fin 11. The protruding portion 12b is joined to the locking portion 12d by a conductive adhesive, crimping, welding, or other means.

  FIG. 5A is a diagram for explaining a state in which the fin 11 formed with the protrusions 12 as shown in FIG. 3B is bent and joined so as to form an acute angle with the plate-like portion. The protruding portion 12b of the protrusion 12 is locked to the locking portion 12c and joined by a conductive adhesive, crimping, welding or other means. In this example, the locking portion 12 c is formed at a position away from the base end of the protrusion 12. When joined in this manner, the protrusion 12 urges the fins in a direction away from the fins, so that the electrical contact state is better than the joined state of FIGS. 4a and 4b. FIG. 5B is a diagram illustrating a state in which the fin 11 formed with the protrusion 12 as shown in FIG. 3B is bent and joined so as to form an obtuse angle with the plate-like portion. The protrusion 12 is joined to the protrusion 12 of the other fin 11 by a conductive adhesive, crimping, welding, or other means. In FIG. 5b, the locking portion 12c is not necessarily required. When the connection is made in this manner, the contact area between the protrusions 12 is increased, so that the electrical contact state is better than the joined state of FIGS. 4a and 4b.

  When the electrical contact state becomes good as shown in FIGS. 5a and 5b, the resistance value due to the contact decreases and the impedance decreases. In addition, the interval between the fins 11 can be made narrower in the joined state in FIGS. 5a and 5b than in FIGS. 4a and 4b. Therefore, many fins 11 can be installed in the same area, and cooling efficiency improves.

  The impedance of the fin assembly 10 having such a configuration will be described. FIG. 6 a is a diagram for explaining the impedance when the fin 11 is joined by the two columns 14 and the six protrusions 12. This corresponds to the fin assembly of the present invention. FIG. 6B is a diagram for explaining the impedance when the fins 11 are joined by only two columns 14. This is the conventional fin assembly. As can be seen from FIGS. 6a and 6b, in the fin assembly of the present invention, the impedance of the projections 12 in addition to the impedance of the pillars 14 is synthesized in parallel. Impedance decreases. For example, if the impedance of the support 14 is R [Ω] and the impedance of the protrusion 12 is r [Ω], the combined impedance is Rr / 2 (3R + r) in the example of FIG. R / 2. For this reason, the potential difference is smaller than in the prior art, and the emission of electromagnetic waves is suppressed.

  Conventionally, it seems that the same effect is acquired by increasing the number of support | pillars 14. FIG. However, if the support | pillar 14 is increased, manufacture will become difficult and manufacturing cost will become high. Providing the protrusions 12 as in the present invention is useful because the ease of manufacturing and the manufacturing cost can be kept low compared to increasing the number of columns 14. Further, unnecessary radiation can be reduced because the EMI level is lowered.

  FIG. 7 is a view showing another structural example of the fin assembly 10. In the fin assembly 10, the protrusion 12 is bent as shown in FIG. 5a. Therefore, in addition to reducing the impedance of the entire fin assembly 10, the number of fins 11 that can be installed in the same frame 13 can be increased as compared with FIG. 2, and the cooling efficiency is improved. Even when the protrusion 12 is used as shown in FIG. 5B, the same effect as that of the fin assembly 10 shown in FIG. 7 can be obtained.

  In addition, although it has set as the structure which provided the support | pillar 14 in said embodiment, these are not an essential requirement in the fin assembly 10 of this invention. The fin assembly 10 may not include the support 14. Variations of the fin assemblies 10 described below may be either provided or not provided with the support posts 14. Further, the protrusion 12 of the fin assembly 10 shown below can be bent and used as shown in FIG. 5a or 5b.

  FIG. 8 is a view showing another structural example of the fin assembly. In the fin assembly 40, each fin 41 has a semicircular shape. Therefore, when the place where the heat sink is installed is semicircular, the shape is suitable for the place. The shape of the fins 41 may be various polygons, circles, and other complicated shapes in addition to rectangles and semicircles, and may be a shape that matches the place where the heat sink is installed. Regardless of the shape of the fin 41, the fin assembly 40 is formed by being joined to the other adjacent fin 41 by the protrusion 42. The support column 14 is fitted into the hole 42a formed by forming the protrusion 42.

  FIG. 9 and FIG. 10 are diagrams showing a structure example of the fin assemblies 50 and 60 in which a plurality of fins 51 and 61 having different lengths from the base ends to the tip ends of the provided protrusions 52 and 62 are arranged. In the fin assembly 50 of FIG. 9, the lengths of the protrusions 52 provided on one fin 51 are different. In FIG. 9, the length of the left protrusion 52 in the drawing is the shortest and becomes longer toward the right. Therefore, the fin interval on the left side in the drawing is narrowed and the fin interval on the right side is widened. FIG. 10 is an exemplary view of a fin assembly 60 having a structure in which the fins 51 constituting the fin assembly 50 of FIG. 9 are alternately joined. These fin assemblies 50 and 60 can take various shapes depending on the place where the heat sink is installed.

  FIG. 11 is a view showing a structural example of the fin assembly 70 constituted by the fins 71 whose length from the base end to the tip end of the protrusion 72 is shortened in the depth direction of the drawing. The fin assembly 70 having such a configuration can be installed even when the cooling portion of the object to be cooled is narrow. As shown in FIGS. 9 to 11, the lengths of the protrusions 52, 62, 72 from the base end to the tip end are set according to the fin interval, so that the fin assemblies 50, 60, 70 can be Can be configured in shape.

  As shown in the fin assemblies 40, 50, 60, 70 shown in FIGS. 8 to 11, depending on the shape of the fins 41, 51, 61, 71 and the size or shape of the protrusions 42, 52, 62, 72, The three-dimensional body 40, 50, 60, 70 can be configured in a desired shape. Moreover, when these are combined, the degree of freedom of the shape of the fin assembly is further increased, and the fin assembly can be variously formed according to the place where the heat sink is installed.

  12 and 13 are diagrams showing structural examples of fin assemblies in which the fins are not flat plates. In the fin assembly 80 of FIG. 12, the fins 81 are formed in a corrugated plate shape. In the fin assembly 90 of FIG. 13, the fins 91 are formed in a plate shape having a triangular wave cross section. In these configurations, in addition to the above-described reduction in impedance, the surface area of the fins 81 and 91 can be made larger than that of the plate-like fins 11 of FIG. Thus, even when the fins 81 and 91 are not flat plates, the fins 80 and 90 can be joined to each other by the protrusions 82 and 92.

  In the heat sink described above, the amount of electric field radiation from the fin assembly is reduced when the fins are joined by the protrusions 12 in addition to the pillars 14 rather than the conventional pillars 14 alone. As described above, this is largely due to impedance reduction. For this reason, when the number of the protrusions 12 is large, the impedance is further reduced, so that the radiated electric field tends to decrease.

  Next, an embodiment of an electronic device incorporating a heat sink according to the present invention will be described with reference to FIGS. 14 and 15 are diagrams schematically showing the internal structure of the electronic device. Here, an example of a heat sink having the heat receiving plate 120, the two heat pipes 131 and 132, and the fin assembly 110 is shown. This heat sink is disposed on the casing 100 of the electronic device as shown. That is, a heat receiving plate 120 is provided on an electronic device, for example, a processor board, disposed at a predetermined portion of the housing 100, and heat generated by the processor board is absorbed by the heat receiving plate 120. The heat absorbed by the heat receiving plate 120 is transmitted to the fin assembly 110 through the heat pipes 131 and 132.

The fin assembly 110 is attached to the side surface of the housing 100, and a plurality of openings are exposed from the opening 101 formed in the housing. That is, air can flow between the air inside the housing 100 and the outside of the housing.
Although illustration is omitted, a fan may be provided behind the fin assembly 110 so that the heat transmitted to the fin assembly 110 may be released to the outside of the housing 100 through the fan and the opening 101.

  14 and 15 show an example of a heat sink in which the heat receiving plate 120 and the fin assembly 110 are connected by two heat pipes 131 and 132, but the number of heat pipes may be three or more. good. Further, when the heat receiving plate 120 is directly attached to the fin assembly 110, a heat pipe is not necessary. Further, when the electronic device is in the vicinity of the fin assembly 110, the heat receiving plate 120 can be omitted. The number of fin assemblies 110 is not limited to one, and the fin assemblies 110 may be divided into a plurality of pieces and attached to the housing 100.

The schematic block diagram of the heat sink by embodiment of this invention. The figure which shows the structural example of a fin assembly. FIG. FIG. 4 is an exemplary diagram of a shape of a protrusion. FIG. The figure explaining the structure which couple | bonds a projection body with another fin. The figure explaining the structure which couple | bonds a projection body with another fin. The figure explaining the structure which couple | bonds a projection body with another fin. The figure explaining the structure which couple | bonds a projection body with another fin. The figure explaining the impedance of a fin assembly. The figure explaining the impedance of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which shows another structural example of a fin assembly. The figure which showed typically the internal structure of the electronic device which incorporated the heat sink. The figure which showed typically the internal structure of the electronic device which incorporated the heat sink.

Explanation of symbols

    10, 40, 50, 60, 70, 80, 90, 110 ... fin assembly, 11, 41, 51, 61, 71, 81, 91 ... fins, 12, 42, 52, 62, 72, 82,92 ... projection, 12a ... hole, 12b ... projection, 12c, 12d ... locking part, 13 ... frame, 14 ... post, 20,120 ...・ Heat receiving plate, 30, 131, 132 ... heat pipe, 100 ... casing of electronic device, 101 ... opening of casing

Claims (17)

A housing for mounting an electronic device capable of generating heat;
A heat receiving medium that absorbs heat generated by the electronic device mounted on the housing;
A heat sink provided in a predetermined portion of the housing;
A heat transfer medium that guides the heat absorbed by the heat receiving medium to the heat sink,
The heat sink is
A plurality of plate-like fins in which a plurality of protrusions are formed in the same direction are arranged, and the plurality of protrusions of each fin are joined to another adjacent fin, and the plurality of protrusions between the fins. Are electrically connected in parallel,
Electronic equipment. A fan for releasing heat transferred to the heat sink from the fin to the outside of the housing;
The electronic device according to claim 1. A heat sink for dissipating heat generated in an object that can generate heat,
A plurality of plate-like fins in which a plurality of protrusions are formed in the same direction are arranged, and the plurality of protrusions of each fin are joined to other adjacent fins. Comprising fin assemblies electrically connected in parallel;
heatsink. The protrusion is bent starting from one side of a plurality of rectangular cutouts provided in the fin.
The heat sink according to claim 3. A cross-sectional shape that matches the shape of the hole formed by bending the notch, and a hollow cylindrical column is fitted into the hole.
The heat sink according to claim 4. The fin includes a locking portion for locking the protrusion of another fin,
The protrusion has its tip locked by the locking portion.
The heat sink according to claim 3. The locking portion has a recess,
The protrusion has a protrusion formed at the tip thereof that matches the shape of the recess, and the protrusion is press-fitted into the recess of the other fin.
The heat sink according to claim 6. The locking portion has a protrusion provided on the fin in a direction opposite to the protrusion, and a tip of the protrusion is locked to the protrusion of the other fin.
The heat sink according to claim 6. The locking portion is provided at a base end portion of the protrusion.
The heat sink according to claim 6. The protrusion is formed so that the length from the base end to the tip is longer than the distance between the fin and the other fin, and the protrusion is joined so as to bias the other fin away.
The heat sink according to claim 3. The protrusion is formed to have a length from the base end to the tip that is longer than a distance between the fins to be joined, and is joined so as to partially overlap the protrusions of the other fins.
The heat sink according to claim 3. The length from the base end to the tip of the plurality of protrusions formed on one fin is constant, and the plurality of fins are arranged in parallel to each other,
The heat sink according to claim 3. The fin is formed in a corrugated plate shape,
The heat sink according to any one of claims 3 to 12. The fin is formed in a plate shape having a triangular wave cross section,
The heat sink according to any one of claims 3 to 12. The distance between at least one pair of fins is non-uniformly arranged, and the length from the base end to the tip end of each of the plurality of projections formed on at least one fin of the pair of fins corresponds to each pair of projections. Formed with a length according to the fin interval,
The heat sink according to claim 3. The distance between at least one pair of fins is non-uniformly arranged, and one protrusion formed on at least one of the pair of fins has a length from the base end to the tip corresponding to the distance between the pair of fins. Formed with a length,
The heat sink according to claim 3. A heat receiving medium that absorbs heat generated in the object to be cooled;
A heat transfer medium that guides the heat absorbed by the heat receiving medium to any one of the walls.
The heat sink according to any one of claims 3 to 16.

Images