Patent ID: 7270048

Claim:
Pump ( 1 ) with an oscillating pump part, comprising a pump housing ( 2 ) with a working chamber ( 3 ) and a crankcase ( 4 ) separated from the chamber by the pump part, a pump drive ( 6 ) with a drive shaft ( 7 ) is located in the crankcase, the drive shaft is mounted on bearings ( 8 , 9 ) arranged in walls of the crankcase, and at least one of the bearings is positioned in a passage hole ( 11 ) in the crankcase wall, the pump has a suction inlet separate from the crankcase, at least one flow channel for equalizing pressure in the crankcase during oscillating motion of the pump part is provided in the crankcase walls and a flow damper is arranged in the at least one flow channel, wherein the at least one flow channel comprises the passage hole ( 11 ) with the at least one bearing, and in a region of the at least one bearing ( 8 , 9 ) positioned in the passage hole ( 11 ) that forms the flow channel, the flow damper is fixed in the housing and covers an open channel cross section of the flow channel to damp inward and outward air flow.