JPH0864735A - Active heatsink - Google Patents

Abstract

PURPOSE: To take out the heat of a heat generating unit such as an LSI actively and facilitates efficient cooling. CONSTITUTION: A rotary plate 31 is made to face a stational plate 34 brought into contact with a heat generating unit 30 to be cooled with a proper air-gap 35 therebetween. The rotary plate 31 is driven to rotate by an electric motor 32. A suction hole 36 which is continuous with the air gap 35 is so provided as to pierce through the stational plate or the rotary plate from the heat generating unit side. The heat of the heat generating unit is actively taken out by the air which is spouted out from the air gap through the suction hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink for cooling a heating element such as an LSI.

[0002]

2. Description of the Related Art Conventionally, as a heat sink for cooling a heating element such as an LSI, a fin type or pin type made of aluminum has been known.

[0003]

However, the conventional aluminum heat sink is a passive device, not an active device that actively pumps out heat.
For this reason, heat tends to be trapped in the central portion of a package such as an LSI, and even if the length of the pins or fins is increased, the efficiency is not improved, and on the other hand, it is bulky. That is, the passive heat sink requires a large occupied space for both the fin type and the pin type and is bulky. Further, there is a problem that a dead area is generated and dust is accumulated, and this tendency is particularly strong in the pin type.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to provide an active heat sink capable of positively pumping out a heating element such as an LSI.

[0005]

In order to achieve the above object, the active heat sink of the present invention has a fixed plate facing a heating element to be cooled, and a fixed plate opposed to the fixed plate with an appropriate air gap. A rotary plate, an electric motor for driving the rotary plate to rotate, and an air intake hole penetrating the fixed plate from the heating element and continuing to the air gap (claim 1).

Instead of the intake hole, an intake hole may be provided from the rotary plate side through the rotary plate and continue to the air gap (claim 2).

In the electric motor, the fixed plate and the rotary plate are composed of a stator and a rotor of the electric motor. A plurality of permanent magnets are arranged on the surface of the rotor in the circumferential direction, and at the outer side in the radial direction of the rotor. A brushless DC motor may be constructed by arranging magnetic pole devices of a required number of phases in the circumferential direction (claim 3).

A groove extending from the center toward the outer peripheral direction can be formed on at least one of the surfaces of the fixed plate and the rotating plate that face each other (claim 4), and the groove is formed in a spiral shape. (Claim 5).

[0009]

Since the principle of the present invention is that air has viscosity, as shown in FIG. 7, even if the disk 31 has an extremely smooth surface, when it is rotated by the electric motor 32, the rotary plate 31 is rotated.
The air 33 near the surface of is driven by the rotation of the rotating plate 31 and is moved in the tangential direction.

Therefore, as shown in FIG. 8, the rotary plate 31, that is, the rotary surface having a smooth surface, is opposed to the fixed plate 34 which is in contact with the heating element 30 to be cooled and has a smooth surface. When the plate 31 is arranged with an appropriate air gap 35 such as a clearance, an air intake hole 36 is provided from the heating pair 30 through the fixed plate 34 to the air gap 35, and the rotary plate 31 is rotated by an electric motor,
Due to the viscosity and the centrifugal force, the air 33 can be blown out in the outer peripheral direction through the air gap 35 from the intake hole 36 provided on the side of the fixed plate 34.
The heat of 0 can be pumped out positively. The present invention provides an active heat sink based on this action.

The heat sink according to claim 1 has the same structure as that shown in FIG. 8, and is an active device for actively pumping out the heat of the heating element to the outside by the air flow blown to the outside from the inside through the intake hole. Becomes Since the intake air continues from the inside of the heating element, the heat at the center of the heating element can be efficiently pumped out. In addition, since there are no bulky parts such as pins and fins, the space occupied by it can be saved.
Further, there is little possibility that a dead area will be generated or dust will be accumulated, and it is possible to make the whole compact, and in particular, it is possible to provide a small device whose height is suppressed.

In the present invention, since the intake hole is provided as an intake hole which penetrates the rotary plate from the rotary plate side and continues to the air gap, outside air is taken in, and this air passes through the air gap to the outside. By blowing out, the heat of the heating element is positively drawn out by the air flow.

According to a third aspect of the present invention, the fixed plate and the rotary plate are constituted by a stator and a rotor of an electric motor, a permanent magnet is provided on the rotor, and a magnetic pole device having a required number of phases is arranged outside the region of the rotor. Since the motor is configured, it is not necessary to separately provide a rotary plate and a fixed plate in addition to the electric motor, and it is possible to open an intake hole at the center of the rotary plate side. Moreover, the coil of the magnetic pole device is efficiently cooled by the air discharged from the outer peripheral edge of the rotor.

According to the present invention, since the groove extending from the center toward the outer peripheral direction is provided on at least one of the surfaces of the fixed plate and the rotating plate which face each other, it becomes easy for the air to be trapped by the groove. The efficiency of blowing out the air is improved, and in the fifth aspect, the groove is formed in a spiral shape, so that the air blowing efficiency is further improved.

In FIGS. 5 and 6, the intake hole 3 is provided on the side of the heating element 30.
In the embodiment shown in FIG. 8 in which 6 is provided, the number of spiral grooves 37 is appropriately provided on the facing surface of the rotary plate 31 to improve the efficiency. Here, the groove 3 having a square groove-shaped cross section as shown in FIG.
Although four 7 are provided, only one or two or more can be provided. The spiral groove 37 is, as shown in FIG.
When the rotation direction of the rotary plate 31 is counterclockwise when viewed from above, it is preferable that the rotary plate 31 is provided as a spiral groove that turns clockwise as it goes toward the outer periphery, as shown in FIG. If necessary, a spiral groove 38 can be formed on the opposing surface of the fixed plate 34 side as well, as shown in FIG.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a semiconductor circuit element (for example, an LSI) 2 that generates a relatively large amount of heat is attached to a printed wiring board 1 serving as a mounting plate, which serves as a kind of heating element. Further, an active heat sink 10 is attached to the printed wiring board 1 in a state of being superposed on the semiconductor circuit element 2 which is a heating element.

The active heat sink is a rectangular plate-shaped stator 11 which is in contact with the semiconductor circuit element 2 through a highly heat conductive grease 3 and functions as a radiator.
And a disk-shaped rotor 12 which is disposed opposite to the surface of the disk-shaped raised portion of the stator 11 with an air gap at a constant interval and has an intake hole 13 formed in the center, and which is erected at four corners of the stator 11. And a magnetic pole device 14 having a total of four phases, which includes a laminated core 15 extending from the stator 11 to the surface of the rotor 12 and an electric coil 16 wound around a standing base of the laminated core 15.

The four-phase magnetic pole devices 14 described above are provided with yokes 17 provided on the outer periphery of the disk-shaped ridge of the stator 11.
Are magnetically linked by. Further, on the surface of the rotor 12, a plurality of magnetic poles, in the present embodiment, six magnetic poles are arranged by embedding permanent magnets 18 in the circumferential direction, and these permanent magnets 18 have four phases as the rotor 12 rotates. It is configured to pass under the magnetic poles of the electric coil 16, that is, below the downward end face of the laminated core 15 of the magnetic pole device 14 of each phase.
The six magnetic poles of the permanent magnet 18 are magnetized to different magnetic poles alternately in the rotating direction of the rotor 12, and function as a DC brushless motor as a whole.

The rotor 12 is rotatably attached to the arm-shaped support member 20 attached to the standing lower attachment posts 19 at the four corners of the stator 11 via bearings 21 having a bearing structure. This also means that the stator 11 and the rotor 12 are integrally assembled by the mounting post 19.

The assembly of the stator 11 and the rotor 12 thus integrated is provided with a mounting post 22 standing on the substrate 1.
The four corners of the stator 11 are attached to the surface of the semiconductor circuit element 2 which is a heat source, so that the stator 11 is closely contacted.

When the excitation of the electric coils 16 of the four-phase magnetic pole device 14 is sequentially switched to rotate the rotor 12, the outside air is introduced from the intake holes 13 due to the viscosity of the air and passes through the surface of the stator 11 as a radiator. Goes out of the heat sink. For this reason, the stator 11 and the semiconductor circuit element 2 in close contact with the stator 11 are positively air-cooled by the outside air.

Further, the electric coil 16 of the magnetic pole device 14 is efficiently cooled by the wind discharged from the outer peripheral edge of the rotor 12.

In summary, in FIG.
A fixed plate 34 that faces 0, a rotary plate 31 that faces the fixed plate 34 with an air gap 35 at an appropriate interval, and an electric motor that drives the rotary plate 31 to rotate.
The air gap 35 is formed from the heating element through the fixing plate.
Although an active heat sink having a structure in which an air intake hole 36 that follows the above is provided is shown, in this embodiment, instead of the air intake hole 36 that penetrates the fixed plate 34 from the heating element 30 side to the air gap 35, the rotary plate 2 Rotor 12 which is a rotating plate from the side
Through the air gap 25 to the air gap 25,
It is configured as an active heat sink that positively pumps out the heat of the heating element 2 by the air blown out from the air gap 25 through the air intake hole 13.

Further, in this embodiment, since the magnetic pole device 14 serving as the excitation phase is arranged outside the rotor 12 in the radial direction, that is, outside the region of the rotor 12, any position in the region of the rotor 12, especially the center of the rotor 12. It is possible to open the intake hole 13 in the air passage, which allows the heat of the heating element to be positively pumped out by utilizing the external air.

In order to enhance the air-cooling effect due to the above-mentioned action, in this embodiment, a spiral groove 23 is formed on the disk surface of the rotor 12 in a spiral shape that spirally extends from the center of the rotor 12 in the rotational direction. . Therefore, as compared with the case of a smooth disk, it becomes easier to capture the air in the groove 23, and the air can be efficiently blown out. The cross-sectional shape of the spiral groove 23 may be a substantially rectangular groove in cross section, but here, as shown in FIG. 3, it is formed as a groove having a curved concave cross section in which the front side is shallow and the rear side is deep in the rotational direction.

Furthermore, a spiral groove can be provided on the surface of the stator 11, and in this embodiment, as shown in FIG. 3, it has a curved concave sectional shape opposite to the groove 23 on the rotor 12 side. A spiral groove 24 made of a groove is formed. In this way, when viewed in the groove cross section, the airflow drawn from the shallow groove side turns into a swirling airflow in the groove center, and this air can be sent as an airflow toward the outer periphery at a high speed so as to wrap it around the deep groove side. The ability to pump out heat can be improved.

Further, the intake hole is not limited to the one that opens at the center of the rotor 12. The same applies to the groove. For example,
As the groove 23 communicating with the central air intake hole 13 moves outward, the interval between adjacent grooves widens. Therefore, a separate groove may be formed within this interval to the outer peripheral edge. In this case, the position of the intake hole opened at the base end is slightly outward from the center of the rotor 12, but if it is located between the bearing 21 and the tip of the laminated core 15, it does not hinder the intake of air.

[0028]

As described above, according to the present invention, in the heat sink according to claim 1, the heat of the heat generating element is positively applied by the air flow that blows out the heat from the inner side to the outside through the intake hole. It can be pumped out. Since the intake hole continues from the inside of the heating element, the heat at the center of the heating element can be efficiently pumped out. In addition, since there are no bulky parts such as pins and fins, it occupies a small space and is less likely to create dead areas or collect dust. Can be kept low.

Further, according to the second aspect, since the intake hole is provided as an intake hole penetrating the rotary plate side from the rotary plate side and continuing to the air gap, the outside air is taken in, and the cold air is introduced into the air gap. The heat of the heating element is positively pumped out because it becomes an air flow that passes through the air and blows to the outside. Therefore, high cooling efficiency can be expected.

According to a third aspect of the present invention, the fixed plate and the rotary plate are the stator and rotor of the electric motor, the rotor is provided with a permanent magnet, and the magnetic pole device is arranged outside the region of the rotor to form a brushless DC motor. Therefore, it is not necessary to separately provide a rotating plate and a fixed plate other than the electric motor, and the structure can be simplified. Moreover, since the intake hole can be provided at the center of the rotary plate side, the central portion of the heating element can be efficiently cooled. Further, since the coil of the magnetic pole device can be cooled by the air discharged from the outer peripheral edge of the rotor, the efficiency is good.

Further, according to the fourth aspect, since the groove is formed on at least one of the surfaces of the fixed plate and the rotary plate which face each other, the air can be easily trapped by the groove and the air can be efficiently blown out. According to the fifth aspect, since the groove is formed in a spiral shape, it is possible to further improve the air blowing efficiency.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view of an active heat sink according to an embodiment of the present invention.

FIG. 2 is a plan view of the active heat sink of FIG. 1 with the support member omitted.

3 is a cross-sectional view of grooves formed in a rotor and a stator of the active heat sink of FIG.

FIG. 4 is a plan view of the fixing plate of FIG.

5 is a plan view of the rotary plate of FIG.

6 is a sectional view showing a spiral groove of the fixing plate of FIG.

FIG. 7 is a perspective view showing the principle of the active heat sink of the present invention.

FIG. 8 is a side view showing the basic configuration of the active heat sink of the present invention.

[Explanation of symbols]

 1 Printed wiring board that functions as a mounting plate 2 Semiconductor circuit element that is a typical heating element 3 High thermal conductivity grease 10 Active heat sink 11 Stator that functions as a radiator 12 Rotor 13 Intake hole 14 Magnetic pole device 15 Laminated core 16 Electric coil 18 Permanent magnet 19 Mounting post 20 Supporting member 21 Bearing 23, 24 Groove 25 Air gap

Claims (5)

[Claims] 1. A fixed plate facing a heating element to be cooled, a rotary plate arranged to face the fixed plate with an appropriate air gap, an electric motor for rotationally driving the rotary plate, An active heat sink characterized in that an air intake hole is provided from the heating element through the fixing plate and continuing to the air gap. 2. The active heat sink according to claim 1, wherein instead of the air intake hole, an air intake hole that penetrates the rotary plate from the rotary plate side and continues to the air gap is provided. 3. In the electric motor, the fixed plate and the rotary plate are composed of a stator and a rotor of the electric motor, and a plurality of permanent magnets are circumferentially arranged on the surface of the rotor, and a radial direction of the rotor is provided. The active heat sink according to claim 1 or 2, which is configured as a brushless DC motor by arranging magnetic pole devices having a required number of phases in the outer circumferential direction. 4. The groove extending from the center toward the outer peripheral direction is formed on at least one of the surfaces of the fixed plate and the rotating plate which face each other. Active heat sink. 5. The active heat sink according to claim 4, wherein the groove is formed in a spiral shape.