| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely cool a semiconductor device by circulating cool air between cooling fins without increasing the sizes of a heat sink. SOLUTION: A heat sink provided with a semiconductor device is mounted at the bottom board of a case and a control unit cools the semiconductor device by circulating cooling wind to the cooling fins of the heat sink. The control unit is provided with a first heat sink 2 whereupon a semiconductor device 4 of a high heating value is mounted, a second heat sink 5 whereupon a semiconductor device 7 with a relatively low heating value is mounted, a cover board 8 which forms an air tunnel 9 and a straightening wane 13 for introducing cooling wind. The second heat sink 5 is arranged with a space between the first heat sink 2, the cover board 8 covers both heat sinks and forms the air tunnel 9 between the bottom board 1a, and the straightening board 13 is composed of a member having an inclined part and is arranged over the side plane of the heat sink 2 and the side plane of the heat sink 5, with its one edge attached to the side plane of the second heat sink 5 and the other edge to the side plane of the first heat sink 2.</p> |
