Corrosion resistant pump

Claim 1

A corrosion resistant pump comprising a drive magnet rotatable by a motor, a driven magnet rotatable by the rotation of the drive magnet, an annular yoke having the driven magnet attached to its outer peripheral surface, a covering layer of corrosion resistant synthetic resin formed over the driven magnet-yoke assembly and defining a shaft bore in the center of the assembly, and a pump rotary shaft extending through the shaft bore of the assembly and fittingly connected to the assembly, the rotary shaft having an impeller at its front end, the pump being characterized in that the shaft bore defined by the corrosion resistant covering layer of the driven magnet-yoke assembly and the rotary shaft are provided, where the shaft is fitted in the bore; with shaft drive connecting means comprising a bored portion and a shaft portion fitting therein, the bored and shaft portions having a cross sectional form other than a circular form, and a plurality of shaft fixing means aligned with each other and with the shaft drive connecting means axially of the rotary shaft and each comprising a bored portion and a shaft portion tightly fitting in the bored portion, the shaft fixing means in the rear being diametrically larger than the shaft fixing means in the front, the diametrically larger shaft fixing means including stepped stopper means for holding the shaft portion thereof to the bored portion thereof against axial displacement.