JP3982936B2 - Heat dissipation structure for electronic elements - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat dissipation structure for cooling an electronic element such as a central processing unit (CPU) to prevent overheating thereof.
[0002]
[Prior art]
Recently, the amount of heat generated by electronic devices such as CPUs has increased due to higher speeds and larger capacities. Accordingly, in order to avoid malfunctions and damage due to temperature rise, heat dissipation and cooling are more effective. There is a need for it. Since computers and servers are required to be as small as possible, heat dissipation rather than cooling is employed to prevent the temperature of electronic elements from rising. For example, heat sinks are superposed on electronic elements such as CPUs, and air cooling fans are attached to increase heat dissipation.
[0003]
The latter structure has problems such as power consumption and noise. In contrast, the former structure that performs natural air cooling does not cause such inconvenience. However, recently, electronic devices having a heat generation amount exceeding the heat dissipation amount due to the natural air cooling have been used. In view of this, a heat dissipation structure has been developed in which a metal block thicker than that is attached to a metal plate that also serves as a base to which various components are attached, and an electronic element is adhered to the metal block. One example thereof is described in Japanese Patent No. 2807415. The structure described in this publication is a structure in which one end of a heat pipe is disposed along a metal plate to which an electronic element is attached, and the other end of the heat pipe is in close contact with the metal plate.
[0004]
Another heat dissipation structure using a heat pipe is described in US Pat. No. 5,339,214. This is because one end portion of the heat pipe is brought into close contact with the lower surface side of the metal block to which the electronic element is attached, the other end portion of the heat pipe is extended in a direction away from the metal block, and the end portion is provided with a number of fins. It is the structure connected with the heat sink which has.
[0005]
[Problems to be solved by the invention]
In the former 2807415 patent publication, heat generated from an electronic element is transmitted to a metal plate through a metal block, and is transmitted from the metal block to a metal plate through a heat pipe. Heat is released from the plate. Therefore, since the metal plate is a heat radiating member for the surrounding air, it is necessary to efficiently transfer heat from the electronic element to the metal plate. However, in the above structure, since a thick metal block is interposed between the electronic element and the metal plate, the thermal resistance between the metal plate and the electronic element is increased, and as a result, from the electronic element. In order to eliminate the heat dissipation efficiency and solve this problem, there is an inconvenience of increasing the size as a whole, such as making the metal block larger or making the heat pipe have a large diameter with a large heat transport capability.
[0006]
Further, in the structure described in the latter US Pat. No. 5,339,214, the base metal plate to which the metal block is attached is not actively used as a means for heat dissipation, so that the heat dissipation efficiency is improved. There was still room for improvement.
[0007]
The present invention has been made against the background described above, and an object thereof is to provide a structure having a simple structure and good heat dissipation efficiency from an electronic element.
[0008]
[Means for Solving the Problem and Action]
In order to achieve the above object, the present invention provides a heat radiating metal plate to which an electronic element that generates heat by operation is attached so as to be able to exchange heat, and stands up from the surface of the heat radiating metal plate and In a heat dissipation structure for an electronic device comprising a plurality of heat dissipation portions provided in a state having a certain length in the surface direction of the metal plate, the heat dissipation portion is sandwiched between a pair of side surface portions and these The heat dissipating part comprises a top surface part facing in parallel with the heat dissipating metal plate and having a hollow structure with open end faces in the length direction, and a suction part provided with a blade that is driven to rotate. The opening end is disposed away from the heat dissipating metal plate, the opening end is disposed opposite to the electronic element attached to the heat dissipating metal plate, and the top surface portion is arranged in the plate thickness direction. many small holes is formed penetrating And it is characterized in that is.
[0009]
Therefore, in the present invention, heat generated from the electronic element is transmitted to the heat radiating metal plate, further transmitted from the heat radiating metal plate to each heat radiating portion, and dissipated from the outer surface to the outside. The heat dissipating part includes a pair of surfaces having a spread in the thickness direction of the heat radiating metal plate, and a surface having a spread in the surface direction of the heat radiating metal plate by connecting tip portions of the surfaces. Since the structure has a wide heat exchange area per unit area of the metal plate for heat dissipation, the heat dissipation is excellent.
[0010]
Furthermore, in the present invention, for example, when a conventionally known fan is used in combination, air flows along the internal space of each heat dissipating part, and between the internal space and its external space through a large number of small holes. In and out of the air. In other words, the air flow generated by the fan makes positive and good contact with the heat dissipating part, thus preventing overheating of the electronic element.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, a specific example in which the present invention is applied to cooling an electronic element mounted on a personal computer will be described with reference to the drawings. A heat diffusion plate 1 corresponding to the metal plate for heat dissipation of the present invention is provided on the bottom surface of a personal computer case (not shown). The heat diffusion plate 1 is a rectangular flat plate made of a metal such as aluminum or an alloy thereof.
[0012]
As an example, two heat sinks 2 are provided on the upper surface portion of the heat diffusion plate 1 in FIG. More specifically, as shown in FIG. 2, each heat sink 2 has a structure in which an extremely thin flat plate made of a metal such as aluminum or stainless steel is bent in a so-called 99-fold shape.
[0013]
More specifically, the heat sink 2 includes a plurality of base surface portions 3 attached in close contact with the heat diffusion plate 1, a plurality of top surface portions 4 facing the heat diffusion plate 1 in parallel, and the top surface portion. 4 and a plurality of side surface portions 5 which are continuous to the edge portion of the base surface portion 3 and orthogonal to the heat diffusing plate 1 are provided. The top surface portion 4, the base surface portion 3, and the side surface portion 5 each form a flat surface. Each top surface portion 4 is formed with a circular small hole 6 penetrating in the thickness direction. As an example, the diameter of the small hole 6 is set to about 1/5 of the width of the top surface portion 4. A large number of small holes 6 are formed at regular intervals in the length direction of the top surface portion 4. In addition, as a formation location of the small hole 6, the side part 5 may be sufficient.
[0014]
The pair of side surface portions 5 and the top surface portion 4 sandwiched between them form a single heat dissipation portion 7. Therefore, each heat dissipating part 7 has a so-called tunnel shape or pipe shape having a linear shape and a rectangular cross section, that is, the heat diffusion plate 1 and the top surface portion 4 opposed to each other in the vertical direction in FIG. An internal space is formed by the side portions 5 facing each other in the left-right direction. That is, the internal space of each heat dissipating part 7 communicates with the external space via each small hole 6.
[0015]
Since the heat dissipating part 7 has the above-described shape, it has an advantage that it is highly rigid despite being made of a thin metal plate, and in particular, the side part 5 is not easily deformed in the tilting direction. Thus, since each heat sink 2 has a structure in which three or four heat dissipating portions 7 are integrally and continuously provided, it can be easily attached to the heat diffusing plate and adjacent to each other. There is an advantage that the thermal resistance between the heat dissipating parts 7 is small.
[0016]
One of the two heat sinks 2 is arranged in the vicinity of the left edge of the heat diffusion plate 1 in FIG. 1 with the heat dissipating portion 7 aligned in the length direction of the heat diffusion plate 1. The total length of the heat sink 2 (the total length of the heat dissipating part 7) is set slightly shorter than the total length of the heat diffusion plate 1.
[0017]
On the other hand, the other heat sink 2 is disposed in the vicinity of the center in FIG. 1 with the heat dissipating part 7 oriented in the length direction of the heat diffusing plate 1. The total length of the heat sink 2 is set to about half of the total length of the heat diffusion plate 1. As a fixing means between the heat sink 2 and the heat diffusing plate 1, means such as adhesion or sintering using an epoxy adhesive having high thermal conductivity can be used.
[0018]
On the other hand, an electronic element 8 such as a CPU is attached to a substantially central position on the top view of the heat diffusion plate 1. That is, the electronic element 8 is provided in a portion of the heat diffusing plate 1 exposed from the heat sink 2 and the heat pipe 9 described later, and thus is opposed to the opening end of the heat dissipating unit 7 disposed on the near side in FIG. It has become a state.
[0019]
Furthermore, two heat pipes 9 having an elliptical cross section or a flat cross section are attached to the upper surface portion of the heat diffusion plate 1 as an example. The total length of each heat pipe 9 is set slightly shorter than the length of the heat diffusion plate 1. The heat pipes are respectively provided in a posture parallel to the heat dissipating part 7 in the central portion in the width direction of the heat diffusion plate 1 and in the vicinity of the edge on the near side in FIG.
[0020]
In addition, as a fixing means of the heat pipe 9 and the heat diffusing plate 1, the adhesion | attachment using an epoxy-type adhesive agent is mentioned. As another means, for example, a mounting groove is formed in advance on the surface of the heat diffusing plate 1, and the container of the heat pipe 9 is deformed to such an extent that the function is not hindered and press-fitted into the mounting groove. By any of these means, the heat pipe 9 is assembled to the heat diffusion plate 1 over its entire length, so that not only high fixing strength is obtained, but also heat transfer between the heat pipe 9 and the heat diffusion plate 1. Will be better.
[0021]
As is well known, the heat pipe 9 encloses a condensable fluid such as water or ammonia as a working fluid with a non-condensable gas such as air degassed inside a pipe whose both ends are hermetically sealed. The heat conduction device further includes a wick for generating capillary pressure as necessary.
[0022]
A micro fan 10 is provided inside the personal computer case. The microfan 10 is installed between the heat diffusion plate 1 and the side wall portion of the personal computer case, and is fixed to the personal computer case by appropriate means. As the microfan 10, an axial fan having a configuration in which a blade 11 that is driven to rotate is provided inside the housing 12 is employed, and the suction portion 13 in the housing 12 faces the opening end of each heat dissipating portion 7. It is installed at.
[0023]
On the other hand, the discharge part 14 in the housing 12 is in a state of facing an exhaust hole (not shown) in the personal computer case. The micro fan 10 has a configuration that can be driven by electric power of a battery (not shown) provided as a standard inside the personal computer case, and is provided as necessary.
[0024]
Next, the operation of the present invention configured as described above will be described. Heat generated by the operation of the electronic element 8 is transmitted to the heat diffusing plate 1, further conducted to the entire heat diffusing plate 1, and transmitted to each heat sink 2. More specifically, the heat possessed by the heat diffusing plate 1 is transmitted to each base surface portion 3 in the heat sink 2 and is conducted to the top surface portion 4 via the side surface portion 5.
[0025]
On the other hand, when the microfan 10 is driven, an air flow toward the microfan 10 is generated inside the personal computer case. Specifically, the air flow that moves between the fins, that is, between the adjacent side surface parts 5 along the arrows shown in FIG. 1, the opening end on the right side of each fin in FIG. Air flows are introduced into the internal spaces of the fins through the holes 6 and move along the internal spaces along the arrows shown in FIG. 1. These air flows are both from the suction portion 15 of the microfan 10 to the housing 14. It goes inside and is sent out of the PC case. In particular, the internal space of the heat dissipating part 7 is a space in which the upper side in the flow direction of the air flow is substantially covered by the top surface part 4, in other words, it is configured as a passage partitioning the periphery. The air flow through the air moves smoothly without stagnation.
[0026]
And the range of each top surface part 4 and the thermal diffusion plate 1 covered by each heat dissipation part 7 and the heat possessed by each side part 5 are transmitted to the air flow passing through the internal space of the heat dissipation part 7. On the other hand, the heat which each side part 5 and each base surface part 3 holds is transmitted to the airflow which passes between the heat dissipation parts 7 between. Furthermore, the heat of the top surface portion 4 is transmitted to the air that continuously enters the internal space of each heat dissipation portion 7 through each small hole 6.
[0027]
The air stream heated by the heat of the heat sink 2 and the heat diffusion plate 1 is discharged to the outside of the personal computer case. That is, the heat of the heat sink 2 is carried outside the personal computer case together with the air flow. As a result, the temperature rise of the electronic element 8 is suppressed or prevented. In addition, since each heat pipe 9 is attached to the heat diffusing plate 1 in a posture parallel to each heat dissipating part 7, the air flow is not obstructed by the heat pipe 9.
[0028]
By the way, a part of the heat of the electronic element 8 is transmitted to one end portion of the heat pipe 9 which is fixed in close contact with the surface of the heat diffusing plate 1, and accordingly, the temperature of one end portion of the heat pipe 9 is changed to the other end portion. Therefore, the heat pipe 9 operates. That is, the working fluid sealed inside evaporates, and the vapor flows to the other end portion where the temperature is low, dissipates heat, and transfers heat to the heat diffusion plate 1 and the heat sink 2 or the surrounding air. Therefore, the heat of the electronic element 8 is carried well and quickly with respect to the surface direction of the heat diffusing plate 1.
[0029]
Since the heat generated in the electronic element 8 is collected in the heat sink 2 having a large heat exchange area in this way and then carried to the outside by the air flow, the temperature rise of the electronic element 8 is reliably suppressed or prevented.
[0030]
Further, in the above heat dissipation structure, the surface area of the heat sink 2 per unit area on the mounting surface of the heat diffusing plate 1 is larger than that of a conventionally known heat sink having a structure including a large number of flat plate fins in parallel. Therefore, the substantial thickness as a whole does not become excessively thick, or the weight does not increase significantly. As a result, it is possible to avoid an increase in the size of the apparatus incorporating the electronic element 8 described above.
[0031]
The electronic element targeted by the present invention is not limited to a CPU, and includes a wide range of general electronic components that generate heat when operated by energization. Furthermore, the metal part that can be used in the present invention is not limited to aluminum or an alloy thereof, and may be another metal such as copper or a magnesium alloy. Further, the electronic element may be attached to a surface of the heat diffusion plate where the heat sink is not attached.
[0032]
【The invention's effect】
As described above, according to the present invention, the heat dissipating part has a hollow structure with both end faces opened in the length direction, and a large number of small holes communicating with the internal space and the external space are formed. In addition to having a wide heat exchange area per unit area of the heat radiating metal plate in the heat dissipating part, it is excellent in contact between the heat dissipating part and the air flow when the air flow is supplied. The heat dissipation from the electronic element can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a specific example in which the present invention is applied to cooling an electronic device mounted on a personal computer.
FIG. 2 is a cross-sectional view showing the structure of a heat sink.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thermal diffusion plate, 2 ... Heat sink, 3 ... Base surface part, 4 ... Top surface part, 5 ... Side surface part, 6 ... Small hole, 7 ... Heat dissipation part, 8 ... Electronic element, 9 ... Heat pipe, 10 ... Micro fan .

Claims (1)

A heat-dissipating metal plate on which an electronic element that generates heat by operation is attached so as to be able to receive and receive heat, and stands up from the surface of the heat-dissipating metal plate, and has a certain length in the surface direction of the heat-dissipating metal plate In the heat dissipation structure of the electronic element consisting of multiple heat dissipation parts provided in the state,
The heat dissipating part is constituted by a pair of side parts and a top part facing in parallel with the metal plate for heat dissipation in a state sandwiched between them, and has a hollow structure with both end faces opened in the length direction. In addition , the suction part provided with a blade to be driven to rotate is opposed to the opening end of the heat dissipating part and is disposed away from the heat radiating metal plate, and the opening end is attached to the heat radiating metal plate. A heat dissipating structure for an electronic element, characterized in that a large number of small holes are formed facing the element and penetrated in the thickness direction on the top surface portion .

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