Heat sink and method of manufacturing the same

This invention belongs to the technical field of a heat sink used for cooling semiconductor elements as well as for other heat exchange applications.

There has been emergence of a heat sink using a heat exchanging fin formed by winding a metal wire having excellent heat conductance into a coil shape. The heat exchanging fin has the advantage of being able to ensure a heat exchanging area in proportion as its relatively narrow mounting dimensions in which the heat sink is incorporated.

As one example of a conventional method for manufacturing the heat sink using the coil-shaped heat exchanging fin, the following method has been known so far.

“Patent Literature 1” discloses a heat sink formed by joining heat fin formed in a coil spring to a flat heat exchanging plate having high thermal conductivity by soldering or laser welding.

[Patent Literature] Japanese Unexamined Patent Publication HEI 6-275746

The heat sink disclosed in the aforesaid “Patent Literature 1” suffers from the disadvantage that the mounting dimensions cannot sufficiently be lessened due to a large space formed in the axial center portion of the heat exchanging fin.

This invention is made to eliminate the drawbacks suffered by the conventional heat sink and seeks to provide a heat sink capable of sufficiently lessening the mounting dimensions of coil-shaped heat exchanging fin to offer a wide versatility and a suitable method for manufacturing the heat sink.

To solve the problems as described above according to the present invention, there is provided the following means.

That is, according to the present invention, there is provided a heat sink comprising a heat exchanging substrate made by forming material having high thermal conductivity into a cylindrical shape, and a heat exchanging fin having coil elements, which is formed by winding a metal wire having high thermal conductivity into a coil and flattening the coil-shaped metal wire in whole with bringing the coil elements in contact with the adjacent ones in their mutually displaced state. The coil fin is secured on the outer surface of the heat exchanging substrate in their wound state.

The flattening of the heat exchanging fin eliminates a large space in the axial center portion of the heat sink without reducing a heat exchanging area, so as to swiftly radiate heat through coherent parts between the adjacent coil elements. In addition, the inner space of the heat exchanging substrate formed in a cylindrical shape can be used for a great range of applications.

Further, the aforementioned heat sink according to the invention is featured in that the heat exchanging substrate is provided in its outer peripheral surface with attaching portions for fitting the inner part of the heat exchanging fin thereinto.

According to the structure as mentioned above, the heat exchanging fin can be secured in position within the attaching portions in the heat exchanging substrate. The attaching portion termed herein means a groove formed in the outer peripheral surface of the heat exchanging substrate or a space formed between protrusions on the outer peripheral surface of the heat exchanging substrate so as to fit the heat exchanging fin thereinto.

Further, the aforementioned heat sink according to the invention is featured in which the heat exchanging fin is continuously formed in a spiral manner relative to the axis line of the heat exchanging substrate.

The structure described above serves to form a common interface for heat exchange on the heat exchanging fin.

Further, the aforementioned heat sink according to the invention is featured in which the heat exchanging fin is divided into rings aligned orthogonal to the axis line of the heat exchanging substrate.

The structure described above serves to form divided interfaces for heat exchange on the heat exchanging fin.

Further, the invention with respect to any of the heat sinks described above is featured in that the heat exchanging substrate is formed by placing ring-shaped washers one on top of the other along the axis with the heat exchanging fin interposed fixedly between the washers.

The structure described above fulfills the heat sink having the washers and heat exchanging fins superimposed in a sandwich state.

Further, the invention with respect to any of the heat sinks described above is featured in that the heat exchanging fin has its outer periphery partially cut off to form a radiation accelerating portion for expediting convection of heat exchange fluid.