JPH07176661A - Heat sink - Google Patents

Abstract

PURPOSE:To obtain a heat sink having uniform heat dissipation properties by eliminating fluctuation in temperature of heat receiving block. CONSTITUTION:The heat sink comprises a heat receiving block 1 to be fixed with a heating element, e.g. a semiconductor element 7, requiring the cooling, a unit 4 for dissipating the transmitted heat, and a plurality of heat pipes 2, 9 having one end buried in the heat receiving block and the other end for dissipating heat through the unit 4, wherein the heat pipes are arranged in parallel while perpendicularly intersecting the flowing direction of air for cooling the unit 4. The heat pipe arranged on the outlet side of cooling air has excellent heat transmission or dissipation characteristics as compared with the pipe arranged on the inlet side of cooling air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced air cooling type heat pipe type heat sink fixed to a heating element, and more particularly,
The present invention relates to a heat sink with improved temperature unevenness of a heat receiving block.

[0002]

2. Description of the Related Art Semiconductor elements such as ICs and LSIs used as switching elements in inverters for vehicles generate heat during operation, and are therefore fixed to heat sinks to promote heat dissipation.

FIG. 4 shows a conventional heat sink, (A)
Is a front view, (B) is a top view, and (C) is a sectional view taken along the line AA of the front view. This heat sink includes a heat receiving block 1 to which a semiconductor element 7 can be fixed on one side or both sides,
It is made of a copper pipe, and is inserted into the heat receiving block 1 in series at a predetermined interval in the cooling air passage direction a,
A heat pipe 2 in which a gap is filled with a low melting point metal 3 and fixed, a plurality of heat radiation fins 4 provided in the length direction of the heat pipe 2, and a partition which is press-fitted and fixed in the heat pipe 2 at both ends via the heat radiation fins 4. It has plates 5 and 6.

Inside the heat pipe 2 inserted into the heat receiving block 1, a working fluid 8 is contained, and the semiconductor element 7
When the heat generated based on the operation of is transferred, the working fluid 8 is evaporated and vaporized to move in the pipe. Hydraulic fluid 8
The evaporated gas transfers heat to the radiating fins 4 via the tube wall,
The radiating fins 4 dissipate heat into the atmosphere by being exposed to the cooling air supplied from the a direction. On the other hand, the evaporated gas of the working liquid 8 contained in the heat pipes 2 and 9 is condensed and liquefied by the heat dissipation, and returns to the heat receiving block 1 side again.

The working fluid 8 is selected on the basis of the ambient temperature in a situation where a heat sink is used, and when used at an ambient temperature of 0 ° C. or lower, a low boiling point working fluid such as a CFC compound which is excellent in low temperature vaporization property. Is built in.

[0006]

However, according to the conventional heat sink, since the heat pipes having the same performance are arranged in series in the passage direction of the cooling air for cooling the radiation fins, the operation of the semiconductor element is accompanied. The temperature of the cooling air passing through the radiating fins that are generating heat rises, causing a difference in operating temperature between the heat pipes on the inlet side and the outlet side of the radiating fins. As a result, there is a problem that temperature unevenness occurs in the heat receiving block in which the heat pipe is embedded. Therefore, an object of the present invention is to provide a heat sink that eliminates temperature unevenness of the heat receiving block and has uniform heat dissipation.

[0007]

SUMMARY OF THE INVENTION According to the present invention, in order to eliminate temperature unevenness of a heat receiving block and provide uniform heat dissipation, a heat receiving block to which a heat generating element such as a semiconductor element requiring cooling is fixed, A plurality of heat dissipating devices that dissipate the generated heat and one end that is embedded in the heat receiving block and that the other end dissipates heat through the heat dissipating device and that is arranged in parallel at right angles to the direction of the cooling air that cools the heat dissipating device. And a plurality of heat pipes are arranged so that the heat pipes arranged on the outlet side of the cooling air have better heat transfer or heat dissipation characteristics than the heat pipes arranged on the inlet side of the cooling air. Providing a heat sink configured.

[0008]

According to the present invention, by disposing the heat pipe having excellent heat transfer or heat dissipation in the direction in which the temperature of the cooling air passing through the heat radiating fins increases, the operating temperature of the heat pipe accompanying the increase in the temperature of the cooling air can be improved. Close the difference.

[0009]

The heat sink of the present invention will be described in detail below. The same reference numerals and reference numerals are attached to the parts having the same configurations as those of the conventional art, and thus the duplicated description will be omitted.

FIG. 1 shows a first embodiment of a heat sink of the present invention, (A) is a front view, (B) is a top view, and (C) is a sectional view taken along the line AA of the front view. In FIG. 1, the cooling air is supplied from the a direction. This heat sink includes a heat pipe 2 provided on the inlet side of the cooling air and a heat pipe 2
The heat pipe 9 is formed with a larger outer diameter and has excellent heat conductivity, and the heat pipe 9 is positioned on the outlet side with respect to the passage direction of the cooling air. The heat pipes 2 and 9 embedded in series in the heat receiving block 1 contain the hydraulic fluid 8,
The low-melting-point metal 3 is filled and fixed in the gap with the heat receiving block 1.

When the heat generated by the operation of the semiconductor element 7 raises the temperature of the heat receiving block 1, the working liquid 8 contained in one end of the heat pipes 2 and 9 is evaporated and vaporized to move in the pipe, The heat is transferred to the radiation fins 4. The radiating fins 4 radiate heat to the atmosphere by being exposed to cooling air.

On the other hand, the cooling air receives heat dissipated when passing from the inlet side to the outlet side of the radiating fins 4, and its temperature rises. Therefore, the radiation fins 4 on the outlet side are exposed to the cooling air whose temperature is higher than that on the inlet side.

Even in such a situation, heat transfer to the radiating fins 4 on the outlet side is promoted by the heat pipe 9 having excellent heat transfer property, and the heat receiving block 1 in which the heat pipe 9 is buried by being exposed to the cooling air. Prevents surface temperature from rising. That is, even if the temperature of the cooling air rises, the heat radiation performance of the radiation fins 4 on the outlet side is not impaired, so that the temperature unevenness of the heat receiving block 1 is eliminated.

FIG. 2 shows a second embodiment of the heat sink of FIG. 1, (A) is a front view, (B) is a top view, and (C) is a sectional view taken along the line AA of the front view. In this heat sink, a heat pipe 2 having the same diameter as the inlet side is arranged in a meandering manner on the outlet side of the radiating fins 4 in the passage direction of the cooling air, thereby enhancing the cooling performance of the radiating fins 4 on the outlet side.

FIG. 3 shows a third embodiment of the heat sink of the present invention, (A) is a front view, (B) is a top view, and (C) is a sectional view taken along the line AA of the front view. In this heat sink, a heat pipe 9 having an outer diameter larger than that of the inlet side is arranged in a meandering manner on the outlet side of the radiating fins 4 with respect to the passage direction of the cooling air, so that the outlet side of the heat sink further than that of the first and second embodiments is provided. The cooling performance of the radiation fin 4 is improved.

According to each of the above-described embodiments, the heat transfer to the heat radiation fins on the outlet side with respect to the passage direction of the cooling air is enhanced so that the temperature of the cooling air rises as the heat radiation fins pass. By obtaining good heat dissipation, it is possible to eliminate temperature unevenness of the heat receiving block.

[0017]

As described above, according to the heat sink of the present invention, the heat receiving block to which the heat generating element such as a semiconductor element requiring cooling is fixed, the heat radiating device for radiating the transferred heat, and the one end receiving the heat. A plurality of heat pipes, which are embedded in a block and have the other end radiating heat through a heat dissipation device and arranged in parallel orthogonal to the flow direction of cooling air for cooling the heat dissipation device. Is configured so that the heat pipes arranged on the outlet side of the cooling air have better heat transfer or heat dissipation characteristics than the heat pipes arranged on the inlet side of the cooling air, eliminating the temperature unevenness of the heat receiving block. It is possible to provide excellent heat dissipation.

[Brief description of drawings]

FIG. 1 shows a first embodiment of a heat sink of the present invention,
(A) is a front view, (B) is a top view, (C) is a sectional view taken along the line AA of the front view.

FIG. 2 shows a second embodiment of the heat sink of the present invention,
(A) is a front view, (B) is a top view, (C) is a sectional view taken along the line AA of the front view.

FIG. 3 shows a third embodiment of the heat sink of the present invention,
(A) is a front view, (B) is a top view, (C) is a sectional view taken along the line AA of the front view.

FIG. 4 shows a conventional heat sink, (A) is a front view,
(B) is a top view and (C) is a sectional view taken along the line AA of the front view.

[Explanation of symbols]

 1 Heat receiving block 2 Heat pipe 3 Low melting point metal 4 Radiating fins 5, 6 Partition plate 7 Semiconductor element 8 Working fluid 9 Heat pipe

Claims (5)

[Claims] 1. A heat receiving block to which a heat generating element such as a semiconductor element requiring cooling is fixed, a heat radiating device for radiating the transferred heat, one end is embedded in the heat receiving block, and the other end is the heat radiating device. And a plurality of heat pipes arranged in parallel orthogonal to the flow direction of the cooling air for cooling the heat dissipation device, wherein the plurality of heat pipes are on the outlet side of the cooling air. A heat sink characterized in that the heat pipe arranged in (1) has a heat transfer or heat dissipation characteristic superior to that of the heat pipe arranged on the inlet side of the cooling air. 2. The heat sink according to claim 1, wherein the plurality of heat pipes are configured to have a larger outer diameter on the outlet side than the inlet side of the cooling air. 3. The heat sink according to claim 1, wherein the plurality of heat pipes are arranged with a large distance between the inlet side and the outlet side of the cooling air. 4. The heat sink according to claim 1, wherein the plurality of heat pipes are arranged linearly on the inlet side of the cooling air and meandering on the outlet side. 5. The heat pipe arranged in a meandering shape has a larger outer diameter than the heat pipes arranged in a straight line in the plurality of heat pipes.
The heat sink according to the item.