Heat sink with a centrifugal fan having vertically layered fins

A heat sink with a centrifugal fan comprising:

• a cover of a prescribed shape including an air intake port, an air discharge port, and a partial circular part;
• a heat receiving block thermally connected to a heat generating part to be cooled;
• a heat conductive bottom portion, thermally connected to one face of said heat receiving block, and engaged to said cover with a space portion disposed therebetween;
• a heat dissipating fin portion comprising a plurality of vertically layered thin fins, received within the space portion, thermally connected to said bottom portion, and including a prescribed shape including at least an air inflow portion;
• an outward air flow passage disposed within the space portion between an inner wall of the partial circular part and peripheral end portions of the vertically layered thin fins of the heat dissipating fin portion;
• and
• a centrifugal fan, a rotating shaft of which is arranged in a vicinity of the air inflow portion of said heat dissipating fin portion, said centrifugal fan intakes air from the air intake port, generates a first outward air flow through spaces disposed between adjacent layered fins of said heat dissipating fin portion, and generates a second outward air flow in said outward air flow passage along an inner wall of said cover toward said air discharge port,
• wherein said heat dissipating fin portion includes fin peripheral side portions formed by a plurality of thin fins which are layered with a prescribed clearance, said fin peripheral side portions including a partial circular face of the air inflow portion facing at least the centrifugal fan with a first end and a second end, a bent face, with a first end and a second end, the first end of the bent face is connected to and coincident with the first end of the partial circular face, the bent face extending along the inner wall of said cover and follows a contour of the inner wall of said cover, a side flat face, with a first end and a second end, the first end of the side flat face is connected to and coincident with the second end of the partial circular face, the side flat face directly contacting the inner wall of the cover, and a discharging face with a first end and a second end, the first end of the discharging face is connected to and coincident with the second end of the bent face and the second end of the discharging face is connected to and coincident with the second end of the side flat face, the discharging face facing the air discharge port and including a first portion, a second portion, and an intermediate portion connecting the first portion and the second portion, the intermediate portion extending substantially parallel to the side flat face such that the second portion is offset towards the centrifugal fan,
• wherein said centrifugal fan is arranged in such manner that a part of an outer surface of the centrifugal fan is adjacent to the partial circular face of the air inflow portion, and a remaining part of the outer surface of the centrifugal fan is adjacent to the inner wall of the cover, and said centrifugal fan generates said second outward air flow in said air flow passage which starts at a prescribed position of the inner wall of the cover and runs along the inner wall of the cover toward said air discharge port,
• wherein said cover includes a face transitional portion in a position of the inner wall corresponding to a border portion of the partial circular face of the air inflow portion and the bent face of the heat dissipating fin portion, said face transitional portion generates said second outward air flow along the inner wall of the cover,
• wherein said second outward air flow widens gradually from said face transition portion toward said air discharge port,
• wherein said second outward air flow is accelerated by a multiplier effect of said face transitional portion and said gradually widening second outward air flow from said face transition portion toward said air discharge port, such that said second outward air flow has a greater velocity than said first outward air flow,
• wherein a portion of the air flow generated by the centrifugal fan flows in a semi-circular manner along the inner wall of the partial circular face of the cover and is then accelerated by the face transitional portion through a channel defined by the bent face and the inner wall of the cover to generate said outward air flow, and
• wherein said first outward air flow and said second outward air flow are joined together at the air discharge port.