Patent ID: 8066495
Filing Date: 2011-11-29
Classification: F04D

Abstract:
1. A turbo vacuum pump comprising: a rotating shaft rotatably supported by bearings; a plurality of rotor blades attached to an overhanging portion of said rotating shaft projecting from one of said bearings in such a state that said rotor blades are stacked in an axial direction of said pump, said overhanging portion of said rotating shaft being a portion which is not supported by said bearing; and a motor rotor attached to said rotating shaft between said bearings for rotating said rotating shaft; wherein said overhanging portion of said rotating shaft has a hole extending from the end of the evacuation side of said rotating shaft to the entirety of said overhanging portion to which said plurality of rotor blades are attached, and said hole formed in said rotating shaft has an open end at said evacuation side of said rotating shaft and a closed end, opposing the open end, located at a lower portion of said overhanging portion of said rotating shaft.