Patent ID: 7645126
Filing Date: 2010-01-12
Classification: F04D

Abstract:
1. A vacuum pump for exhausting a gas, comprising: a main shaft rotatably supported by a bearing; a motor for rotating said main shaft; and centrifugal drag vanes attached to said main shaft, wherein each of said centrifugal drag vanes has a cylindrical portion fitted with said main shaft and has a blade portion fixed to an outer surface of said cylindrical portion; said blade portion has a spiral blade integrally connected to said outer surface of said cylindrical portion and a disk-shaped base, said disk-shaped base having a low pressure side to which said spiral blade is fixed and a high pressure side of which no blade is fixed; an axial length of said cylindrical portion is larger than that of said blade portion; an axial length of said spiral blade is continuously reduced in a radially outward direction.