JP2554596B2 - heatsink - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink used for an LSI having a high heat generation density such as a high-speed driving microcomputer, a semiconductor element such as a medium capacity thyristor or a power transistor, and in particular, an air-cooling type for diffusing and cooling heat generation to reduce the size Heat sink that is required to be made

[0002]

2. Description of the Related Art QFP (Quad Flat Pack)
6 and 7 showing a perspective view and a side view showing an example in which a conventional heat sink is attached to an LSI of a ceramic package by aging), the heat sink 90 is made of a material having high thermal conductivity such as aluminum or copper. Heat conduction column 91
Is machined so as to have a fin portion 92 in the peripheral portion of the QFP type LS in which the central portion of the pillar portion 91 serves as a heat source.
The heat generated by the LSI 93 is radiated by the fin portion 92, which is closely mounted on the central plane of the I93.

[0003]

In the heat sink 90 having the above-described structure, the fins of the heat sink 90 are increased by increasing the diameter dl of the fin portion 92 or increasing the number of fins as the heat generation amount of the LSI 93 increases. A sufficient heat dissipation effect cannot be obtained unless the surface area of the portion 92 is increased. However, when d1 of the heat sink 90 is larger than the outer shape of the LSI 93 or the height H becomes too high, such a large heat sink 90 is electronically operated. If it is installed in a limited narrow space such as a device, there is a problem that convection of air is disturbed and the cooling capacity is significantly lowered.

Even if the above-mentioned means for allowing the heat sink 90 to be upsized is used, simply increasing the diameter dl of the fin portion 92 or increasing the number of fins does not mean that the heat source (LS) is used.
I93), the thermal resistance of the material of the heat sink 90 increases as the distance from the heat sink 90 increases, so that it is necessary to increase the thickness t1 of the fins or increase the diameter d2 of the heat conduction column 91, and thus the heat generation amount of the LSI. As a measure against the increase in the number of times, the size of the heat sink is often increased, and at the same time, the size of the motor such as forced convection is often increased, resulting in a high cost.

In the processing of the heat sink 90, the ratio of the diameter d2 of the heat conducting column portion 91 to the diameter d1 of the fin portion 92 is suitable for convection with the fin interval t2 in view of the relationship between the heat sink material and the strength and cutting accuracy of the cutting tool. Since there is a limit that can be cut while maintaining a constant interval, there is a limit to partial miniaturization such as thinning the fin thickness t1 of the heat sink 90.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a small and lightweight heat sink structure for improving heat dissipation performance, and to solve the above problems.

[0007]

In order to solve the above problems, according to the present invention, in a heat sink having a structure in which a heat receiving plate 11 and at least one heat radiating fin 12 are superposed, the heat radiating fins 12 of the heat receiving plate 11 are arranged. Motor on the side
A fan 22 is attached to the rotating shaft of the motor 24, a convection hole 30 is provided between the heat radiation fin 12 and the fan 22, and the fan 22 is provided on the heat receiving plate 11 and the heat radiation fin 12. The heat sink is characterized in that it is configured so that the convection from it directly strikes. Also, the heat receiving plate
A rotating shaft of a motor 24 may be provided between the heat sink plate 11 and the heat radiating fins 12 in parallel with the heat receiving plate surface, and the fan may be a sirocco fan 26, or a side wall 20 may be provided on a part of the outer circumference of each heat sink 10. Good.

[0008]

[Function] As described above, the fin projection 12a is formed on the radiation fin 12.
By providing the above, since the heat of the heat receiving plate can be effectively transmitted to each of the heat radiation fins 12, the conventional heat conduction column portion 91 is unnecessary, and therefore the effective heat radiation area of the fin portion 92 becomes extremely large. Further, since the radiating fin 12 can be provided with the convex portion 12a at an arbitrary position, even if the thickness t1 of the fin portion 92 is made as thin as possible, it is possible to compensate for the increase in the thermal resistance of the fin portion. Since the motor 24 and the fan 22 are arranged at the position of the conductive support 91, a small and lightweight heat sink having excellent heat dissipation effect can be obtained even if the amount of heat generated by a semiconductor heating element such as an LSI increases. If the side wall 20 is provided on the outer circumference, the flow of the atmosphere can be controlled, so that a heat sink structure excellent in soaking can be obtained.

[0009]

1 is a top view of a heat sink according to a first embodiment of the present invention, and FIG. 1 is a view of FIG. 2 taken along the line AA in the direction of the arrow. In FIGS. 2 and 1, the heat sink 10 is made of a material having a high thermal conductivity such as aluminum or copper in a flat plate shape.
The heat receiving plate 11 and the heat radiating fins 12 are processed into a quadrangle, and one surface of the heat receiving plate 11 is attached to a heating element as a heat receiving surface.
A heat radiation fin 12, a motor 24, and a fan 22 are arranged.

In this embodiment, the radiation fins 12 are laminated with four sheets having the same outer diameter as the heat receiving plate 11, and a large number of fin projections 12a are provided below each of the radiation fins 12 to face each other. Are joined by brazing or the like. Further, in this embodiment, the convection hole 30 (space) is a portion where the heat conduction column portion 91 shown in the prior art is abolished, that is, the central portion of the flat plate surface of the radiation fin 12. Of the radiation fins 12, the lowermost convection hole 30 of the uppermost radiation fin 12 (toward the heat receiving plate 11)
A motor 24 having a rotary shaft arranged so as to be perpendicular to the heat radiation fins 12 is attached to the motor, and a fan 22 is attached to the motor rotary shaft. The end surface of the rotation shaft of the motor 24, which does not project, is formed by a support column and a ventilation hole (air introduction hole) as shown in FIG. 2, and air is introduced into the fan 22 through the ventilation hole.

FIG. 4 is a top view of a heat sink as a second embodiment of the present invention, and FIG. 3 is a view of FIG. 4 taken along the line AA in the direction of the arrow. 4 and 3, the rotation axis direction of the motor 24 of the first embodiment is arranged parallel to the heat receiving plate 11, and the motor 24 is provided on the uppermost radiation fin 12 of the first embodiment. On the other hand, in this embodiment, a sirocco fan 26 is provided which is provided in the central axis direction of the two opposite sides of the heat receiving plate 11 on the other surface side, and which is connected to the motor 24 in the axial direction and rotates. . Side walls 20 are provided from the heat receiving plate 11 to the uppermost radiation fin 12 on three of the four sides of the flat heat sink 10, and convection into and out of the heat sink 10 (inflow and outflow of the atmosphere) is indicated by arrows in FIG. As shown in FIG. 3, the process is performed only on one side where the side wall 20 is not provided.

In the second embodiment, structures other than those described above are the same as or equivalent to those in the first embodiment, and the description thereof will be omitted.

FIG. 5 is a top sectional view of a heat sink according to a third embodiment of the present invention. In the second embodiment, the motor 24 and the sirocco fan 26 are disposed on the outer periphery of the heat receiving plate 11. The configuration is the same as that described in the first embodiment except that the side wall 20 is arranged on one side and the side wall 20 is provided on two sides of the side opposite to the side on which the motor 24 is arranged and the side adjacent thereto. The description is omitted because it is the same as or equivalent to.

In each of the above embodiments, the motor 24
Needless to say, if a temperature sensor is provided and driven and stopped depending on the state of the heating element, power consumption can be saved. Further, the shape of the heat sink 10 and the radiation fins in the above embodiment
Number of 12 shapes, fin protrusion 12a, convection hole 30, motor 2
4. The position, shape, number, and number of side walls of the fan 22 are one example, and can be arbitrarily changed. Further, although the radiating fins 12 of the above embodiment are all provided with the convection holes 30, the uppermost radiating fins that do not affect the operation of the fan 22 may have a fin structure without the vent holes 30. In this case, the convection air is introduced through the lower surface of the upper radiation fin or the radiation fin 12.
It is introduced from a hole (not shown) formed at an appropriate position in the above, or a vent hole provided in the motor 24.

[0015]

In the conventional heat sink, the heat conducting pillar 91 is used as the main heat radiation portion, but in the present invention, instead of this, a large number of fin projections 12a are provided between the respective heat radiation fins 12 to improve heat dissipation. Radiating fins even when compared to the conductive post 91
Since the motor 24 and the fan 22 for generating forced convection can be arranged in the convection hole 30 because of excellent heat conduction between the heat sinks 12, the heat sink 10 originally having a structure in which the heat radiation fins 12 are superposed has a small and lightweight characteristic. It can be extracted in two and can be easily arranged even in a small space on a circuit in a highly integrated electronic device, and an extremely excellent heat dissipation effect can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view of the heat sink of FIG. 1 taken along the line AA in the arrow direction.

FIG. 2 is a top sectional view of a heat sink as a first embodiment of the present invention.

FIG. 3 is a top sectional view of a heat sink as a second embodiment of the present invention.

FIG. 4 is a perspective view of a conventional heat sink.

FIG. 5 is a side view of a conventional heat sink.

FIG. 6 is a perspective view of a conventional heat sink.

FIG. 7 is a side view of a conventional heat sink.

[Explanation of symbols]

 In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 10 Heat sink 11 Heat receiving plate 12 Radiating fin 12a Fin convex part 20 Side wall 22 Fan 24 Motor 26 Sirocco fan 30 Convection hole

Claims (3)

(57) [Claims] 1. A heat sink having a structure in which a heat receiving plate and at least one heat radiating fin are superposed on each other, and a motor is provided on a side of the heat receiving plate where the heat radiating fin is disposed, and a fan is attached to a rotating shaft of the motor. A heat sink characterized in that a convection hole is provided between the radiating fin and the fan so that the heat receiving plate and the radiating fin are directly contacted with convection from the fan. 2. A heat sink having a structure in which a heat receiving plate and at least one heat radiating fin are superposed on each other, and a rotating shaft of a motor is provided between the heat receiving plate and the heat radiating fin in parallel with a surface of the heat receiving plate, and the fan is sirocco. A heat sink used as a fan. 3. The heat sink according to claim 1, wherein a side wall is provided on a part of the outer circumference of the heat sink.