Patent Application
20120247735
The present invention relates to a heat sink used for cooling a component to be cooled in an electronic device, for example, a heat-generating component such as CPU or MPU.
Recent years have seen significant advances in enhancing of the performance and downsizing of various electric or electronic devices such as personal computers. However, enhancement of the performance of CPU, MPU and the like mounted on a notebook PC, laptop and desktop PC causes an increase in heat generation. Meanwhile, glowing demands for downsizing of the electric or electronic devices require space saving in the electronic or electronic devices.
Cooling of a higher-performance heat-generating component such as CPU or MPU is always one of most important technical problems. Besides, also in electric or electronic devices other than computers, cooling of a higher-performance heat-generating component or element becomes one of most important problems in view of the demands for space saving in the electric or electronic devices.
As a method of cooling an electronic component mounted in the electric or electronic device, there is known a method of directly cooling a component to be cooled by a cooler mounted on the component to be cooled. As such a cooler mounted on the component to be cooled, a heat sink is often used which is composed of a base plate that is a plate member made of a material having excellent heat conductivity such as copper or aluminum and thin plate fins bonded to one surface of the base plate.
The above-mentioned method of dissipating heat of the component to be cooled by the thin plate fins provided on the base plate as a heat receiving section to receive heat from the component to be cooled is generally used as a heat dissipater of an electric device. In the conventional art, the heat sink (heat dissipater) having the base plate and heat dissipating fins provided on the base plate has been often made of extruded aluminum with which the base plate and the heat dissipating fins are formed integrally with each other, but now, copper is used to enhance the heat dissipating performance.
The copper is excellent in heat conductivity. However, when the base plate is large or the heat source is provided at one side of the base plate, the heat spread effect (effect of heat transfer to the entire part of the base plate) is not enough. In such a case, the heat dissipating performance is improved by providing the base plate with a heat pipe or a vapor chamber thereby to enhance the spread effect of heat transfer to the base plate entirely and enhance the heat dissipating performance.
The vapor chamber is high-cost and it is necessary to include hole forming for mounting screws in first designing, which causes a problem of loss of design flexibility. Besides, the case of burying the heat pipes in the copper block, machining is required such as cutting of grooves to bury the heat pipes, which causes a problem of high cost. In order to solve these problems, there is adopted a configuration in which heat pipes are sandwiched between two plate members of the first plate member and the second plate member. With this configuration, machining such as cutting for fixing the heat pipes can be eliminated thereby to achieve cost cutting. Further, a space is created around the heat pipes, which leads to reduction in the weight of the base part and total weight reduction.
Inside the heat pipe to move heat to a desired position, a space is provided as a fluid path of working fluid. The working fluid accommodated in the space is moved or phase-changed by evaporating, compressing or the like so that the heat moves. That is, at the heat absorbing side of the heat pipe, the working fluid is evaporated by heat generated by the component to be cooled transferred in a material of the heat pipe case, and its vapor is moved to the heat dissipating side of the heat pipe. At the heat dissipating side, the vapor of the working fluid is cooled and returned to a liquid state again. In this way, the working fluid returned into the liquid state moves to the heat absorbing side again (back-flow). Such phase transformation and movement of the working fluid causes heat movement.
When the heat pipes are sandwiched between the two plate members that are the first plate member and the second plate member, the ends of the heat pipes are spread in only one of the width and longitudinal directions. However, at the part where the plural heat pipes are in contact with the component to be cooled, they are gathered at the center so as to move the heat efficiently from the component to be cooled. Therefore, the space is created at the side surfaces of the heat pipes and the heat cannot be transferred sufficiently to the heat dissipating fins positioned corresponding to the space, which causes a problem of insufficient heat dissipation.
Further, if a metal block is buried in the entire part of the heat sink for the purpose of transferring heat to the space at the side surfaces of the heat pipes, the steps of cutting or machining of the grooves for burying the heat pipes as described above become complicated and the cost becomes problematically high.
Accordingly, the present invention aims to provide a high-performance heat sink that that has reduced machining processes, light-weight and reduced costs and is capable of improving heat dissipating performance.
The inventors of the present invention have studied diligently to solve the conventional problems. As a result, they have found that heat can be effectively dissipated in end directions and side surface direction of the heat pipes by transferring the heat via the heat pipes and the first plate member at the ends of the heat pipes and thermally connecting the metal block with excellent heat conductivity at the side surfaces of the heat pipes, without need to use a metal block all over the heat sink.
A first aspect of the present invention is a heat sink comprising: a first heat transfer plate member that has one surface thermally connected to a heat generating component and is thermally connected to a first heat dissipating fin section having thin plate fins; a second heat transfer plate member that has one surface thermally connected to a second heat dissipating fin section having thin plate fins; a heat pipe section that is provided between an opposite surface of the first heat transfer plate member and an opposite surface of the second heat transfer plate member to be thermally connected thereto; and a heat transfer block that is thermally connected to a side surface and an upper surface of the heat pipe section and arranged to sandwich the heat pipe section between the heat transfer block and the second heat transfer plate member.
The heat sink according to a second aspect of the present invention is characterized in that the heat pipe section comprises a plurality of heat pipes that are arranged side by side (arranged in a line), at least one of the heat pipes has a bent part, and the heat transfer block is arranged to be thermally connected to side surfaces of outermost heat pipes of the heat pipes and upper surfaces of the heat pipes.
The heat sink according to a third aspect of the present invention is characterized in that the thin plate fins of the first heat dissipating fin section are arranged in parallel to each other and vertical to the surface of the first heat transfer plate member and spaced from each other by a predetermined distance along a width direction of the first heat transfer plate member at a longitudinal end or over the surface of the first heat transfer plate member.
The heat sink according to a fourth aspect of the present invention is characterized in that the thin plate fins of the second heat dissipating fin section are arranged in parallel to each other and vertical to the surface of the second heat transfer plate member and provided in a longitudinal direction and almost over the surface of the second heat transfer plate member.
The heat sink according to a fifth aspect of the present invention is characterized in that each of the heat pipes has a planular shape, the heat pipes are arranged in parallel to each other and in contact with each other at least at center thereof, and the bent part of the heat pipe is arranged along an end of the second heat transfer plate member on which the second heat dissipating fin section is arranged.
The heat sink according to a sixth aspect of the present invention is characterized in that each of the heat pipes has a planular shape, the heat pipes are arranged in parallel to each other and spaced from each other so as to be out of contact from each other, and the bent part of the heat pipe is arranged along an end of the second heat transfer plate member on which the second heat dissipating fin section is arranged.
The heat sink according to a seventh aspect of the present invention is characterized in that one of the heat pipes, which is arranged at a center along a longitudinal direction, is formed linearly, and the heat pipes, except for the linear (straight) one at the center, are arranged symmetric or asymmetric with respect to the center and linear heat pipe arranged along a longitudinal direction of the second heat transfer plate member.
The heat sink according to an eighth aspect of the present invention is characterized by further comprising a fixing portion for fixing the first heat transfer plate member and the second heat transfer member at a peripheral part of the heat sink while the heat pipe section is sandwiched between the first heat transfer plate member and the second heat transfer plate member.
According to the present invention, the heat sink is configured to sandwich the heat pipes between two plate members that are the first plate member and second plate member, and at least one heat pipe is elongated in the longitudinal direction or ends of plural heat pipes are spread in the longitudinal direction and width direction, parts of the heat pipes in contact with a component to be cooled are set at the center and the block having excellent heat conductivity is arranged at a space formed at the side surfaces of the heat pipes. With this structure, it is possible to transfer the heat to the heat dissipating fins at the position corresponding to the space sufficiently, thereby improving the heat dissipating performance.
With reference to the drawings, description is made about a heat sink according to the present invention.
The heat sink according to an aspect of the present invention has a first heat transfer plate member that is thermally connected at one surface to a heat generating component and also thermally connected to a first heat dissipating fin section composed of thin plate fins, a second heat transfer plate member that is thermally connected at one surface to a second heat dissipating fin section composed of thin plate fins, a heat pipe section that is provided between the opposite surface of the first heat transfer plate member and the opposite surface of the second heat transfer plate member and thermally connected to them and a heat transfer block that is thermally connected to an upper surfaces and side surfaces of the heat pipe section and thermally arranged so as to sandwich the heat pipe section between the heat transfer block and the second heat transfer plate member.
As illustrated in
The upper and lower surfaces of the plural heat pipes 7-1 to 7-5 are in contact with the first heat transfer members 2-1, 2-2 and the heat receiving section 10 and thermally connected thereto. Besides, each of the end block parts 6-1, 6-2 of the heat transfer block 6 takes the shape of a thicker block, and the side surfaces of the end block parts 6-1, 6-2 are in contact with side surfaces of the outmost heat pipes 7-5, 7-1 and thermally connected thereto.
At an end of the surface of the first heat transfer plate member 2-1 (lower side in
The first heat dissipating fin section 5 bonded to the first heat transfer plate member 2-1 and the second heat dissipating fin section 4 bonded to the second heat transfer plate member 3 need not to be formed integrally by extrusion and may be formed by bonding plural fins to the heat transfer plate members at a desired fin pitch.
As described above, between the heat receiving section 10 of the heat transfer block 6 and the second heat transfer plate member 3, and between the first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3, the plural heat pipes 7-1 to 7-5 are sandwiched and thermally connected thereto. In the aspect illustrated in
Further, the plural heat pipes 7-1 to 7-5, except the heat pipe 7-3 arranged at the center, are arranged so as to be spread in the width direction of the first and second heat transfer plate members at the side of the first heat dissipating fin section 5. Particularly, an end of each of the heat pipes 7-2, 7-4 is bent at right angles and extends in the width direction along the first heat dissipating fin section. An end of each of the other heat pipes 7-1, 7-5 is arranged in such a manner as to be spread in the width direction of the second heat transfer plate member so that the heat is transferred in the width direction of the heat transfer plate member to the entire thin plate fins bonded to the second heat transfer plate member 3.
The plural heat pipes 7-1 to 7-5 are thermally connected and vertically sandwiched between the first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3, except at the position of the heat transfer block 6. Besides, the plural heat pipes 7-1 to 7-5 are arranged with no space therebetween and in contact with each other at the center parts thereof in the width direction at the position of the heat transfer block 6 and they are vertically sandwiched between and thermally connected to the second heat transfer plate member 3 and the heat receiving section 10. The outermost heat pipes 7-1, 7-5 are in contact at side surfaces thereof with the end block parts 6-2, 6-1 of the heat transfer block 6.
The surface of the heat receiving section 10 of the heat transfer block 6 which is out of contact with the heat pipes 7-1 to 7-5 forms a heat receiving surface that is connected to the heat source and the heat received by the heat receiving surface is transferred to the heat pipes 7-1 to 7-5. With such a configuration, the heat received by the heat receiving surface of the heat receiving section 10 is transferred via the heat transfer block 6 to the lower surfaces and side surfaces of the plural heat pipes, thereby enabling efficient heat transfer to the heat pipes. Here, the heat pipes are preferably arranged with side surfaces in contact with each other, but they may be arranged in parallel out of contact with a space therebetween. If the heat pipes are arranged out of contact, the heat receiving section 10 is used to transfer heat to each of the heat pipes.
In the aspect illustrated in
The upper surfaces of the end block parts 6-1 and 6-2 are bonded to the second heat transfer plate member 3 by soldering or the like. With this bonding, the heat from the heat receiving section 10 can be transferred to the second heat transfer plate member 3 efficiently. Here, the end block parts 6-1, 6-2 and the second heat transfer plate member 3 are separate from the first heat transfer members 2-1, 2-2 and the first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3 are preferably fixed at the contact portion (for example, fixing parts 8 at the four corners) by solder bonding or the like. Besides, it is also preferable that the first heat transfer plate members 2-1, 2-2 and the heat transfer block 6 are bonded at the contact portion to each other by soldering.
Heat transferred to the heat receiving section 10 from the heat generating component (heat source) is transferred from the back surface of the heat receiving section 10 to the plural heat pipes and diffused in the lateral direction to the end block parts 6-1, 6-2. That is, the heat transferred from the heat generating component to the heat receiving section 10 is transferred to the plural heat pipes 7-1 to 7-5 that are in direct contact with the opposite surface to the heat receiving surface of the heat receiving section 10. Then, the heat of the heat receiving section 10 is transferred to the end block parts 6-1, 6-2 and then to the side surfaces of the heat pipes 7-1, 7-5. Further, the end block parts 6-1, 6-2 and the heat pipes are thermally connected to the second heat transfer plate member 3 and heat received by the heat receiving section 10 is transferred via them to the almost entire part of the second heat transfer plate member 3. Consequently, the heat is transferred to the second heat dissipating fin section 4 having plural thin plate fins bonded to the almost entire part of the upper surface of the second heat transfer plate member 3 and dissipated from the heat dissipating fins to the outside of the heat sink.
A first cover 9-1 is provided at one end of the second heat dissipating fin section 4 and a second cover 9-2 is provided at each side of the center part of the heat sink 10. The first and second covers 9-1, 9-2 are used as covers when packaging the heat sink of the present invention. Preferably they have cushioning properties and may be made of porous resin or sponge, for example.
A second heat dissipating fin section 4 composed of thin plate fins is arranged as thermally connected to almost entire surface of a surface of the second heat transfer plate member 3 (upper side in
The first heat dissipating fin section 5 and the second heat dissipating fin section 4 are formed at a desired fin pitch on the first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3, respectively. Between the first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3, a plurality of heat pipes 7-1 to 7-5 arranged side by side each other are sandwiched as thermally connected thereto.
Around the center part of the second heat transfer plate member 3 in the longitudinal direction, the plural heat pipes 7-1 to 7-5 are arranged in contact with each other with no space therebetween. The center part of the plural heat pipes is thermally connected to the heat transfer block 6 having excellent heat transfer performance. In the heat transfer block 6, the heat receiving section 10 at the center part and both-sides end block parts 6-1, 6-2 made of metal having excellent heat transfer performance are formed integrally. Heat transferred from the heat-generating component (heat source) to the heat receiving section 10 of the heat transfer block 6 as a heat receiving surface is transferred to the plural heat pipes 7-1, 7-2, 7-3, 7-4, 7-5 and end block parts 6-1, 6-2. The heat is then, transferred to the almost entire area in the vertical and horizontal directions of the second heat transfer plate member 3 by the plural heat pipes 7-1 to 7-5 and end block parts 6-1, 6-2.
The first heat transfer plate members 2-1, 2-2 and the second heat transfer plate member 3 are thermally connected to the first heat dissipating fin section 5 and the second heat dissipating fin section 4, and fixed by a fixing section 8 sandwiching the heat pipes 7-1 to 7-5 arranged side by side. The plural heat pipes are arranged to be thermally connected at their center parts to the heat transfer block 6 made of metal with excellent heat transfer property. The heat transfer block 6 has end block parts 6-1, 6-2 which are formed at both sides and made of metal with excellent heat transfer property and the heat receiving section 10, and the end block parts 6-1, 6-2 and the heat receiving section 10 are formed integrally.
The heat transfer block 6 comprises the block parts 6-1, 6-2 and the heat receiving section 10. The block parts 6-1, 6-2 are arranged in contact with the linear side surfaces at the centers of the outermost two heat pipes 7-1, 7-5 and the heat receiving section 10 is contact with the upper surface at the center of the plural heat pipes 7-1 to 7-5. The heat generated by the heat generating component is diffused in the lateral direction by such a heat transfer block 6 above. Consequently, the heat is diffused entirely to the heat sink and dissipated via the heat dissipating fins to the outside of the heat sink.
In the aspect illustrated in
In the aspect illustrated in
In the aspect illustrated in
The thin plate fins according to the aspects illustrated in
As described above, according to the present invention, it is possible to provide a high-performance heat sink that is manufactured by a smaller number of mechanical works, light weight and low-cost and capable of enhancing the heat-dissipating performance.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-041467 | Feb 2010 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2011/053827 | Feb 2011 | US |
| Child | 13455717 | US |
