| 摘要 |
PROBLEM TO BE SOLVED: To save power and space and to reduce noise by providing at least one cooling fin or more of which the density of radiating fins in the lower part near a fin base is smaller than in the upper part. SOLUTION: A density of provision of radiating fins 713 and 733 of cooling fins 71 and 73 fitted to semiconductor devices 31 and 33 in the uppermost- stream-side array and the lowermost-stream-side array becomes smaller in the part below support fins being nearer to a fin base than in the part above them. On the other hand, the density of provision of radiating fins 723 of a cooling fin 73 fitted to a semiconductor device 32 in the central array is made uniform. In other words, the cooling fin 71 on the uppermost-stream side and the cooling fin 73 on the lowermost-stream side radiate heat mainly by the radiating fins 713 and 733 above support fins 712 and 732, while the central cooling fin 72 radiates heat mostly by the radiating fin 723 below a support fin 722. Therefore the cooling fins 71, 72 and 73 can execute cooling with temperature differences among them lessened. |
