Patent ID: 7942648

Claim:
An air pump comprising: a pump section ( 100 ) for compressing and blowing air; a motor section ( 200 ) in contact with the pump section ( 100 ) for driving the pump section ( 100 ); and a shaft ( 222 ) positioned from the pump section ( 100 ) to the motor section ( 200 ) and supported by two ball bearing units ( 142 , 152 ) at a base portion thereof, wherein the pump section ( 100 ) comprises: a cylinder ( 111 ) having a tubular inner wall, a front plate ( 141 ) attached to one end of the cylinder ( 111 ) on an opposite side of the pump section ( 100 ) from the motor section ( 200 ), a rear plate ( 151 ) attached to another end of the cylinder ( 111 ) on the same side of the pump section ( 100 ) as the motor section ( 200 ), a plurality of pump spaces ( 161 ) surrounded by the cylinder ( 111 ), the front plate ( 141 ) and the rear plate ( 151 ), and a rotor ( 121 ) positioned in the pump space ( 161 ) and attached to the shaft ( 222 ) to be rotatably driven thereby, wherein the shaft ( 222 ) and cylindrical rotor ( 121 ) are eccentric with respect to an axis of the tubular inner wall of the cylinder ( 111 ), the rotor ( 121 ) includes a plurality of axially extending slits ( 122 ), plane-shaped vanes ( 131 ) are fitted in the slits ( 122 ) to define the plurality of pump spaces ( 161 ) within the cylinder ( 111 ), one of the two ball bearing units ( 142 ) is attached to the front plate ( 141 ), another of the two ball bearing units ( 152 ) is attached to the rear plate ( 151 ), the shaft ( 222 ) has a top portion in the motor section ( 200 ), and the motor section ( 200 ) comprises: a motor rotor ( 221 ) connected to the top portion of the shaft ( 222 ), wherein the distance between the connecting position of the motor rotor ( 221 ) and the shaft ( 222 ) and the rear plate ( 151 ) is less than the distance between the axial center (S) of the stator ( 211 ) and the rear plate ( 151 ), a casing ( 231 ) connected to the rear plate ( 151 ) for covering the motor rotor ( 221 ), and a stator ( 211 ) positioned farther away from the rear plate ( 151 ) than the motor rotor ( 221 ) and supported in the casing ( 231 ) by the rear plate ( 151 ) for generating a rotating magnetic field for the motor rotor ( 221 ).