JPS5844755A - Forcibly cooling heat sink - Google Patents

Abstract

PURPOSE:To obtain a heat sink which has preferable heat dissipating characteristic by dividing part of metal cooling fins implanted in parallel with each other in a bimetal structure. CONSTITUTION:A heat sink 5 is integrally mounted on the back surface of a substrate 2 which carries a heat generating body, and fins 3 and a bimetal structure 6 are provided in parallel with each other. When the quantity of heat is increased and the heat sink 5 becomes high temperature, a bimetal structure 6 is bent, causing the flow of the fluid to be disordered. Accordingly, the heat dissipating characteristic of the heat sink is enhanced. The bent is increased as the temperature rises, thereby increasing the effect, followed by operating to maintain the temperature of the heat generating body constant.

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to a tormentor for forced cooling.

In electronic devices, it is very important to maintain a constant temperature of a heating element such as an L8I from the viewpoint of operational reliability of the device.

Conventionally, in the heat sink used for forced cooling in this type of device, the fins 3 have a rectangular planar shape, and a plurality of fins are installed in parallel on the heat sink 1, as shown in FIG. ing. The heat dissipation characteristics of the heat sink 1 are determined by the size of the temperature difference between the heat sink 1 and the surrounding fluid 4, assuming that the amount of heat transferred from the heat sink 1 to the surrounding fluid 4 is constant, and the smaller the temperature difference, the better. The temperature difference T between the heat 7 tank 1 and the surrounding fluid 4 is expressed by the following equation (1).

ΔT=Q/(αx8xφ)・・・・−・−・−・(1)
Here, Q: Heat transferred from heat sink 1 to surrounding fluid 4 α: Heat transfer coefficient 8: Surface constraint of heat sink 1 in contact with surrounding fluid 4 φ: Efficiency of fin 3 of heat sink 1 In equation (1), S and φ It is determined by the shape of the heat sink 1, and since QFi is considered to be constant, ΔT is inversely proportional to α, and it can be seen that the larger α is, the smaller the temperature difference between the heat sink 1 and the surrounding fluid 4 is. Further, α changes depending on the degree of turbulence in the flow of the surrounding fluid 4, and becomes larger as the flow becomes more turbulent. Therefore, the temperature difference △T between the heat sink 1 and the surrounding fluid 4 becomes smaller as the flow of the surrounding fluid 4 becomes more turbulent. However, in the case of a conventional heat sink, when this turbulence is less
Therefore, it had the disadvantage of poor heat dissipation characteristics.

An object of the present invention is to provide a heat sink having a structure with excellent heat dissipation characteristics.

In order to achieve the above object, the forced cooling heat sink according to the present invention is a heat sink in which a plurality of rectangular flat plate-like fins are planted in parallel on a metal flat plate box, in which a part of the fins is separated to form a bimetal structure. It's Nishide.

According to the above configuration, when the temperature rises, the bimetallic structure fins curve, which disturbs the flow of the surrounding fluid and improves the heat dissipation characteristics, so that the object of the present invention is completely achieved.

Next, the present invention will be explained in detail with reference to the drawings. FIG. 2 is a perspective view showing an embodiment of the present invention.

A heat sink 5 is integrally provided on the back surface of a substrate 2 on which a plurality of heat generating elements such as L8I (not shown) are mounted, and a heat sink 5K [similar to conventional fins 3 and a bimetal structure section 6 having a bimetal structure are arranged in parallel, The fins 3 arranged in parallel are also erected.

The heat sink according to the present invention configured as described above has the same fin shape as the conventional heat sink 1 as shown in FIG. When the heat generation amount of the fin 3 increases and the temperature of the heat sink 5 increases, as shown in FIG.
The bimetallic structure (6 ends) is curved to allow fluid to flow through the 1. This creates a protrusion and has the effect of disrupting the flow.

First, α in the above-mentioned equation (1) becomes large, and the heat dissipation characteristics of the heat sink 5 can be improved. This effect,
As the temperature of the heat sink 5 becomes higher, the curvature of the bimetal structure 6 becomes larger and increases, which acts to keep the temperature of the heating element constant.

Note that the bending direction and position of the bimetal structure 6 shown in the embodiments of the present invention described above are different from each other. etc. are also included in the present invention.

As explained above, the present invention improves heat dissipation characteristics by forming part of the fins of the heat sink into a bimetallic structure, so that the bimetallic structure curves as the temperature of the heating element rises and disturbs the flow of the surrounding fluid. It has the effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a conventional heat sink, and FIG. 2 is a perspective view showing an embodiment of a heat sink according to the present invention. 1.5...Heat sink 2...Substrate 3...Fin 4...Surrounding fluid 6...Bimetal structure Patent applicant NEC Corporation Agent Masuji I) B Jusai Figure 1 Figure 2 (a) (b) 265-

Claims (1)

[Claims] 1. A heat sink for forced cooling comprising a plurality of rectangular flat plate-shaped fins planted in parallel on one side of a flat metal plate, characterized in that a portion of the fins is separated to form a bimetallic structure.