Patent ID: 7544049
Filing Date: 2009-06-09
Classification: H01L

Abstract:
1. A centrifugal pump comprising: a pump casing made of thermally conductive material and having a pump room defined therein, said pump casing including a casing base wall; an impeller rotatably mounted in said pump room for rotation about a rotary axis extending in a thickness direction of said pump casing; wherein said casing base wall has an inner wall face facing said impeller in the thickness direction; wherein said casing base wall has an outer wall face opposite said inner wall face, said outer wall face being provided in a heat receiving plane and configured to receive heat from a component; wherein said inner wall face includes a radially inner surface and a radially outer surface, said radially outer surface being disposed outwardly of said radially inner surface with respect to said rotary axis; wherein said radially inner surface and said radially outer surface are disposed at different levels in the thickness direction so as to be at different distances from said impeller; wherein said inner and outer surfaces both face an interior of said pump room, and said radially inner surface constitutes a recessed area that is recessed, relative to said radially outer surface away from said impeller; wherein said inner wall face further includes a step portion formed between said radially inner surface and said radially outer surface; wherein a surface-area-increasing part is formed in said recessed area so as to project in the thickness direction toward said impeller from said radially inner surface; wherein said pump casing further includes a peripheral side wall having an inwardly facing surface that defines an outer boundary of said pump room; wherein said radially outer surface has an outer periphery defined by said inwardly facing surface of said peripheral side wall of said pump casing, and said radially outer surface extends continuously from said outer periphery thereof to said step portion; and said radially outer surface of said inner wall face of said base wall of said pump casing constitutes a surrounding area that surrounds said recessed area and is disposed closer to said impeller than said recessed area, and said step portion of said inner wall face constitutes a sloped portion as a transition between said recessed area and said surrounding area, said sloped portion gradually sloping from said recessed area toward said impeller.