JP2000151169A - Radiation structure of electronic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide structure that can efficiently radiate heat from an electronic element via a metal plate and has small heat resistance. SOLUTION: In the radiation structure of an electronic element that transfers heat generated from an electronic element 4 to a metal plate 1 for radiation, and at the same time radiates the heat from the metal plate 1 for radiation, one part with specific area of the metal plate 1 for radiation projects in the direction of the thickness of the plate for forming a protrusion part 2, at the same time, a top surface part 3 of the projection side of the protrusion part 2 is set to a pedestal part for mounting the electronic element 4, one end part of a heat pipe 7 passing through the side surface of the protrusion part 2 is allowed to adhere to a rear surface part opposite to the top surface part 3, and at the same time the other end part of the heat pipe 7 is arranged along a surface that continues to the top surface part 3 of the metal plate 1 for radiation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiation structure for cooling electronic elements such as a central processing unit (CPU).

[0002]

2. Description of the Related Art Recently, the amount of heat generated by electronic devices such as CPUs has been increasing due to the increase in speed and capacity, and in order to avoid malfunction or damage due to a rise in temperature, it has become more effective. Heat dissipation and cooling are increasingly required. Since computers and servers are required to be as small as possible, means for radiating heat rather than cooling are employed to prevent the temperature of electronic elements from rising. For example, a heat sink is attached to an electronic element such as a CPU, and an air-cooling fan is attached to promote heat dissipation.

The latter structure has problems such as power consumption and noise, while the former structure in which natural air cooling is performed does not cause such inconvenience. However, recently, electronic devices having a heat generation amount exceeding the heat radiation amount by the natural air cooling have been used. Therefore, a heat dissipation structure has been developed in which a thicker metal block is attached to a metal plate also serving as a base on which various components are attached, and an electronic element is adhered to the metal book. One example is described in Japanese Patent No. 2807415. The structure described in this publication, one end of the heat pipe,
The heat pipe has a structure in which the electronic element is arranged along a metal plate and the other end of the heat pipe is brought into close contact with the metal plate.

Another heat dissipation structure using a heat pipe is described in US Pat. No. 5,339,214. This means that one end 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 of the heat pipe is extended in a direction away from the metal block, and a large number of fins are formed on the end. It is a structure connected to a heat sink.

[0005]

SUMMARY OF THE INVENTION The former No. 280741
In the structure described in Patent Document 5, heat generated from an electronic element is transmitted to a metal plate via a metal block, transmitted from the metal block to a metal plate via a heat pipe, and radiated from the metal plate. It is supposed to. 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 the thick metal block is interposed between the electronic element and the metal plate, the thermal resistance between the metal plate and the electronic element increases, and as a result, The heat dissipation efficiency is lowered, and in order to solve this, there is a disadvantage that the size of the metal block is made larger, or the heat pipe is made of a large diameter having a large heat transfer capacity, for example.

Further, in the structure described in the latter US Pat. No. 5,339,214, a metal plate serving as a base to which a metal block is attached is not actively used as a means for radiating heat. There was still room for improvement in improving efficiency.

The present invention has been made in view of the above circumstances, and has as its object to provide a structure that is simple in structure and has good heat dissipation efficiency from an electronic element.

[0008]

In order to achieve the above object, the invention described in claim 1 transmits heat generated from an electronic element to a metal plate for heat radiation and simultaneously transmits the heat to the metal plate for heat radiation. In the heat dissipating structure of the electronic element dissipated from the plate, a part of a predetermined area of the heat dissipating metal plate is protruded in the plate thickness direction to form a raised portion,
A top surface on the protruding side of the raised portion serves as a pedestal portion for mounting the electronic element, and one end of a heat pipe penetrating the side surface of the raised portion is brought into close contact with a back surface opposite to the top surface portion. And the other end of the heat pipe is arranged along a surface continuous with the top surface of the metal plate for heat radiation.

Therefore, according to the first aspect of the present invention, since the top surface of the raised portion is a pedestal for mounting the electronic element, the mounting position of the electronic element becomes clear and the portion protruding from the pedestal is provided. Is provided on the electronic element,
By disposing a fixing member such as a screw or a clamper between the protruding portion and the metal plate, the electronic element can be securely and firmly adhered to the pedestal portion and fixed. Therefore, since the electronic element has a structure in which the electronic element is directly attached to the metal plate, heat generated from the electronic element is directly transmitted to the metal plate and radiated from the metal plate. The heat resistance is reduced and heat can be efficiently radiated. In addition, the heat pipe having one end adhered to the lower surface (back surface) of the pedestal portion transports heat to a part of the metal plate away from the pedestal portion, so that substantial heat dissipation in the metal plate is achieved. In this respect, the heat radiation efficiency from the electronic element via the metal plate can be improved.

According to a second aspect of the present invention, in the first aspect, the protrusion amount of the raised portion is a thickness measured in a thickness direction of the heat-dissipating metal plate at one end of the heat pipe adhered to the back surface. It is characterized in that the protrusion amount is as described above.

According to the second aspect of the present invention, the heat pipe is inserted into and closely attached to the lower surface (back surface) of the pedestal portion by penetrating the side surface of the raised portion, so that the heat pipe exceeds the height of the raised portion. Therefore, it is possible to eliminate a factor of increasing the size of a device in which the electronic element is incorporated.

According to a third aspect of the present invention, in the configuration of the first aspect, a metal block is attached to the back surface so that one end of the heat pipe is sandwiched between the back surface and the heat pipe. Is what you do.

According to the third aspect of the invention, heat is transferred from the metal plate to the metal block, and one end of the heat pipe is sandwiched between the metal block and the metal plate. Since the heat transfer area to the pipe is increased and the heat transfer efficiency is improved, and the heat capacity of the metal block is increased, even if there is sudden heat generation in the electronic element, this heat is absorbed by the metal block and the Temperature rise can be prevented beforehand.

According to a fourth aspect of the present invention, in the configuration of the third aspect, the thickness of the metal block is set to a thickness that does not protrude from a concave portion formed on the back surface side of the raised portion. It is characterized by the following.

Therefore, according to the fourth aspect of the present invention, even if a thick metal block is used, the thick metal block can be accommodated inside the raised portion, so that the overall thickness does not increase. Factors of upsizing of a device into which an electronic element is incorporated can be eliminated.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to a specific example shown in the drawings. In FIG. 1, reference numeral 1 denotes a heat diffusion plate (corresponding to a metal plate of the present invention) made of a metal such as aluminum or an alloy thereof, and the heat diffusion plate 1 is a rectangular or rectangular thin plate material. Although not shown, a necessary notch may be provided in the peripheral portion, or a screw hole, a through hole, and a cut-and-raised piece may be appropriately formed.

A protruding portion 2 protruding from one surface (tentatively referred to as a surface) is formed in a part of the heat diffusion plate 1. The raised portion 2 can be formed, for example, by drawing (coining) a part of the heat diffusion plate 1, and has a truncated pyramid shape as an example. The top surface portion 3 of the raised portion 2 has a flat square or rectangular shape, where CP
An electronic element 4 such as U is attached in close contact. Therefore, the top surface 3 is a pedestal for the electronic element 4.

On the predetermined side surface 5 of the above-mentioned raised portion 1,
A through hole 6 is formed. One end of the heat pipe 7 is inserted into the through hole 6, and one end of the heat pipe 7 extending from the through hole 6 to the back surface (lower surface) of the top surface 3 is in close contact with the back surface of the top surface 3. It is fixed at.

Here, the heat pipe 7 has a condensable fluid such as water as a working fluid in a state in which a non-condensable gas such as air is degassed inside a pipe whose both ends are hermetically sealed. And a wick for generating capillary pressure as needed therein. As an example, a copper pipe is used for the pipe, and therefore, the heat pipe 7 has a flexible structure.
The heat pipe 7 has a basically circular cross section, but the inside of the raised portion 1, that is, one end inserted on the back surface side of the top surface portion 3 is processed into an elliptical cross section or a flat cross section. This is to make the contact area of the top surface portion 3 with the back surface as large as possible.

FIG. 2 shows an example of a structure for fixing one end of the heat pipe 7. In the fixing structure shown in FIG. 2A, one end of a heat pipe 7 crushed into an elliptical cross section or a flat shape is brought into close contact with the back surface of the top surface portion 3, and in this state, the heat pipe 7 is bonded with an adhesive 8 such as an epoxy resin. 3 is fixed to the back surface.

The fixing structure shown in FIG.
A block 10 made of metal such as aluminum or an alloy thereof having a recess 9 for accommodating one end of
The metal block 10 is fixed to the back surface of the top surface 3 with one end of the heat pipe 7 fitted in the recess 9, so that one end of the heat pipe 7 is fixed to the back surface of the top surface 3. is there. In addition, as a means for attaching the metal book 10 to the back surface of the raised portion 2, an appropriate means such as welding, bonding, screwing, fixing with a clamp piece, and rivets can be adopted.

The fixing structure shown in FIG.
This is an example using. That is, the metal band 11 is a band-shaped member made of a metal such as aluminum or an alloy thereof, and the metal band 11 is applied to the lower surface of one end of the heat pipe 7 which is in close contact with the back surface of the top surface portion 3. By fixing both ends to the back surface of the top surface portion 3, one end of the heat pipe 7 is fastened by the metal band 11 and fixed to the back surface of the top surface portion 3. The means for fixing the metal band 11 to the back surface of the top surface 3 may be any suitable means such as welding, bonding, screwing, and rivets.

In any of the examples shown in FIGS. 2A to 2C, the metal block 10 and the metal band 1
The thickness of one end of the heat pipe 7 including the first protrusion 1 is set smaller than the protrusion amount of the raised portion 2. As a result, the entire end of the heat pipe 7 including the means for fixing the heat pipe 7 is housed inside the raised portion 2 so as not to protrude to the back side of the heat diffusion plate 1. In other words, the protrusion amount of the raised portion 2 is set to a protrusion amount that can completely accommodate the heat pipe 7 and the like on the back surface side.

The heat pipe 7 is curved in an L-shape as shown in FIG. 1, and the other end is arranged along the surface of the heat diffusion plate 1 and It is fixed in close contact. The means for fixing is not particularly shown, but means such as bonding, a metal band or a cut-and-raised elastic piece can be employed.

Here, an example of a structure for fixing the electronic element 4 to the raised portion 2 will be described. As shown in FIG.
Is formed, and the flange portion 4a is
Is set to a length that protrudes to the left and right of the raised portion 2 in a state where is placed on the top surface portion 3. And this flange part 4a
By screwing a screw (not shown) penetrating through the heat diffusion plate 1, the electronic element 4 is fixed in close contact with the top surface 3. In this case, since there is a gap between the flange portion 4 a and the heat diffusion plate 1, there is no member that directly generates a stress that directly resists the tightening force of the screw. Can be fixed firmly. The fixing means, that is, the fastener, may be replaced by a screw and an appropriate elastic clamper. The clamper may be formed by cutting and raising a part of the heat diffusion plate 1.

In the above structure, the top surface 3 of the raised portion 2 has C
An electronic element 4 such as a PU is directly attached. The heat generated by the operation of the electronic element 4 is transmitted directly from the top surface portion 3 to the raised portion 2, from which heat is conducted to the entire heat diffusion plate 1 and dissipated to the surrounding air. .
At the same time, heat is transmitted to one end of the heat pipe 7 which is fixed in close contact with the back surface of the top surface 3, and accordingly, the temperature of one end of the heat pipe 7 becomes higher than the temperature of the other end. Therefore, the heat pipe 7 operates. That is, the working fluid enclosed therein evaporates, and the vapor flows to the other end having a low temperature to radiate heat, and transfers heat to the heat diffusion plate 1 and the surrounding air. In this way, the heat generated in the electronic element 4 is diffused and dissipated through the heat diffusion plate 1 and the heat pipe 7, so that the temperature rise of the electronic element 4 is suppressed or prevented.

In the above-described structure, the raised portion 2 serving as a pedestal portion for mounting the electronic element 4 is formed by deforming a part of the heat diffusion plate 1 and forming a part of the heat diffusion plate 1. In addition, the thermal resistance when heat is transmitted from the electronic element 4 to the heat diffusion plate 1 becomes extremely small.
The heat radiation characteristics via the substrate are improved. Further, since one end of the heat pipe 7 is directly adhered and fixed to the back surface of the top surface 3 to which the electronic element 4 is attached, the electronic element 4 is fixed.
Therefore, the heat resistance when transmitting heat to the heat pipe 7 is reduced, so that the heat pipe 7 can efficiently carry heat away from the electronic element 4 and suppress or prevent a temperature rise of the electronic element 4. .

Further, in the above structure, the mounting portion for mounting the electronic element 4 is formed by projecting a part of the heat diffusion plate 1 to the surface side, so that the mounting position of the electronic element 4 is clarified. In addition, the electronic element 4 can be securely and firmly fixed, and the cost can be reduced by reducing the number of components and eliminating the need for a conventional metal block. Become. Further, one end of the heat pipe 7 is completely housed inside the raised portion 2,
Since there is no member protruding on the rear surface side of the device, the overall thickness can be substantially reduced, and as a result, an increase in the size of the device incorporating the electronic element 4 can be avoided.

Next, still another example of the present invention will be described with reference to FIG.
This will be described with reference to FIG. The example shown here has a configuration in which the raised portion 2 is projected in two steps, and the heat pipe 7
This is an example in which the other end is connected to a heat sink 12 and a thick metal block 13 is provided inside the raised portion 2.

That is, the raised portion 2 is projected in two steps so that a flat portion is formed at an intermediate portion in the height direction, and the most protruding top surface portion 3 serves as a pedestal portion for mounting an electronic element. I have. A through hole 6 for inserting one end of the heat pipe 7 is formed on the side surface bent in two steps, and one end of the heat pipe 7 crushed in a flat shape is connected to the top surface 3 by the through hole 6. Is inserted on the back side of the
Is adhered to the back surface of

On the other hand, a heat sink 12 is fixed to the peripheral portion of the heat diffusion plate 1 adjacent to the raised portion 2. As shown in FIG. 4, the heat sink 12 is formed by integrally forming a large number of thin fins on the upper surface side of a rectangular parallelepiped block, and the block shape is formed along the hand direction on the lower surface side of the block. The other end of the heat pipe 7 formed with a concave groove and curved in a U-shape is closely fitted inside the concave groove. Therefore, the heat pipe 7 is arranged along the surface of the heat diffusion plate 1. The fins are formed along the width direction of the block, that is, along the direction perpendicular to the heat pipe. This is to reduce the width of each fin so as to prevent deformation at the time of manufacture and thereafter. Further, when air is blown, the flow path of the air between the fins is short, so that the flow resistance of the air is reduced, and the flow of the cooling air is improved, so that the heat radiation efficiency can be improved.

A metal block 13 is arranged inside the raised portion 2. The metal block 13 is made of a metal such as aluminum or an alloy thereof, and is a rectangular member thicker than the heat diffusion plate 1. On the upper surface side of the metal block 13, a concave groove 13 a for fitting one end of the heat pipe 7 adhered to the back surface of the top surface portion 3 is formed, and the concave groove 13 a and the back surface of the top surface portion 3 A metal block 13 is fixed to the rear surface of a flat portion in the middle of the protruding portion 2 in a state where one end of the pipe 7 is sandwiched therebetween. The fixing means may be an appropriate means such as a screw or an adhesive. The metal block 13
Is set to a thickness that does not protrude downward (downward in the figure) from the back surface of the heat diffusion plate 1 on the lower surface side of the raised portion 2.
This is to reduce the substantial thickness and avoid an increase in the size of the device in which the electronic element is incorporated, as in the example described above.

In the configuration shown in FIGS. 3 and 4, the electronic element is mounted on the top surface 3 of the raised portion 2.
The heat generated from the electronic element is first transmitted to the raised portion 2 which is a part of the heat diffusion plate 1, and diffuses from there to the entire heat diffusion plate 1 and is radiated to the surrounding air. Further, the heat pipe 7 is in close contact with the raised portion 2 and the back surface of the top surface portion 3.
Is transferred to the heat sink 12 by the heat pipe 7. The heat sink 12
Since the heat pipe 7 is in close contact with the other end of the heat pipe 7 and a large heat radiation area is secured by a large number of fins, the heat carried by the heat pipe 7 is efficiently radiated from the heat sink 12. You. In particular, if air is blown in the direction of the surface of the fins, the air flows smoothly and the heat radiation efficiency is improved.

Therefore, also in the examples shown in FIGS. 3 and 4, since heat is directly transmitted from the electronic element to the heat diffusion plate 1, heat can be efficiently radiated through the heat diffusion plate 1. In addition, the fact that heat can be efficiently radiated through the heat pipe 7 is the same as in the examples shown in FIGS. 1 and 2 described above. Furthermore, in the example shown in FIGS. 3 and 4, the metal block 13 having a large heat capacity due to being thick is attached inside the raised portion 2.
When the electronic element generates a large amount of heat suddenly, before the heat is diffused by the heat diffusion plate 1 and the heat pipe 7, the metal block 13 absorbs heat corresponding to the heat capacity. Therefore, it is possible to prevent a rapid rise in the temperature of the electronic element.

In each of the above-described examples, the electronic device, the heat pipe, the metal block, and the like are configured to be directly mounted on the heat diffusion plate.
The term "includes" means that a filler that mediates heat transfer, such as a so-called thermal joint, may be interposed, and does not exclude the existence of this kind of inclusion that has been generally performed conventionally. Further, the electronic element targeted by the present invention is not limited to the CPU, and includes a wide variety of general electronic components that generate heat when operated by being energized. Furthermore, the metal parts that can be used in the present invention are not limited to aluminum or its alloys, but may be other metals such as copper and magnesium alloys.

[0036]

As described above, according to the first aspect of the present invention, since the top surface of the raised portion is a pedestal for mounting the electronic element, the mounting position of the electronic element becomes clear and the pedestal is mounted. A part protruding from the part is provided on the electronic element, and a fixing member such as a screw or a clamper is arranged between the protruding part and the metal plate to securely and firmly adhere the electronic element to the pedestal part Can be fixed. Therefore, since the electronic element has a structure directly attached to the metal plate, the heat generated from the electronic element is directly transmitted to the metal plate and radiated from the metal plate.
The heat resistance between the electronic element and the metal plate is reduced, so that heat can be efficiently radiated. In addition, the heat pipe having one end adhered to the lower surface (back surface) of the pedestal portion transports heat to a part of the metal plate away from the pedestal portion, so that substantial heat dissipation in the metal plate is achieved. In this respect, the heat radiation efficiency from the electronic element via the metal plate can be improved.

According to the second aspect of the present invention, the heat pipe is inserted into and closely attached to the lower surface (back surface) side of the pedestal portion by penetrating the side surface of the raised portion. The overall thickness is not increased beyond the height, so that the factor of increasing the size of the device in which the electronic element is incorporated can be obviated.

Further, according to the third aspect of the present invention, heat is transferred from the metal plate to the metal block, and one end of the heat pipe is sandwiched between the metal block and the metal plate. Since the heat transfer area to the heat pipe is increased and the heat transfer efficiency is improved, and the heat capacity of the metal block is increased, even if there is sudden heat generation in the electronic element, the heat is absorbed by the metal block and the electronic element is absorbed. Temperature can be prevented beforehand.

According to the fourth aspect of the present invention, even if a thick metal block is used, it can be accommodated inside the raised portion, so that the overall thickness does not increase. Therefore, it is possible to obviate the factor of increasing the size of the device into which the electronic element is incorporated.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of the present invention.

FIG. 2 is a diagram showing an example of a structure for fixing one end of the heat pipe to the back surface of the top surface, and is a cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a sectional view showing another example of the present invention.

FIG. 4 is an exploded perspective view thereof.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heat diffusion plate, 2 ... Ridge part, 3 ... Top surface part, 4 ... Electronic element, 6 ... Through-hole, 7 ... Heat pipe, 13 ...
Metal block.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Koichi Mashiko 1-5-1 Kiba, Koto-ku, Tokyo Inside Fujikura Co., Ltd. (72) Inventor Kazuhiko Goto 1-1-5-1 Kiba, Koto-ku, Tokyo Stock Company Inside Fujikura Corporation (72) Inventor Tan Nuen 1-5-1, Kiba, Koto-ku, Tokyo F-term in Fujikura Corporation (reference) 5E322 AA01 AA11 AB11 DB09 DB10 FA01

Claims (4)

[Claims] 1. A heat dissipating structure for an electronic element for transmitting heat generated from an electronic element to a heat dissipating metal plate and dissipating the heat from the heat dissipating metal plate, wherein a part of a predetermined width of the heat dissipating metal plate is: A projecting portion is formed by projecting in the thickness direction, and a top surface portion of the projecting side of the projecting portion serves as a pedestal portion for mounting the electronic element, and a heat pipe penetrated through a side surface of the projecting portion. One end is brought into close contact with the back surface opposite to the top surface, and the other end of the heat pipe is arranged along the surface of the metal plate for heat dissipation that is continuous with the top surface. A heat dissipation structure for an electronic element, characterized by: 2. The projecting amount of the raised portion is set to be equal to or greater than a thickness measured in a thickness direction of the heat-dissipating metal plate at one end of the heat pipe adhered to the back surface. The heat dissipating structure for an electronic device according to claim 1, wherein: 3. The heat radiating structure for an electronic element according to claim 1, wherein a metal block is attached to the back surface with one end of the heat pipe sandwiched between the back surface and the heat pipe. . 4. The electronic device according to claim 3, wherein a plate thickness of the metal block is set so as not to protrude from a concave portion formed on a rear surface side of the raised portion. Heat dissipation structure.