Vacuum pump

摘要

A vacuum pump includes a housing (14) assembly having an oil-reservoir chamber in which a lubricating oil is stored; a pair of screw rotors (21,31) disposed in the housing assembly and engaged with each other; a pair of rotary shafts (25) connected to the rotors, respectively; a plurality of bearings (42,43) supporting each of the rotary shafts (25) and having an opening; an oil-feed pump (62) for feeding the lubricating oil from the oil-reservoir chamber (58) to the bearing; an oil-circulation passage provided for circulating the lubricating oil from the oil-feed pump to the oil-reservoir chamber through the bearing; a cover (80) provided at the opening of the bearing to close the opening of the bearing with a clearance remained, the cover permitting the lubricating oil (59) to enter the bearing (51) through the clearance; and an oil-escape passage (85) provided adjacent to the bearing for returning to the oil-reservoir chamber (58) the lubricating oil not entering the bearing.