Motor with electrodynamically and hydrodynamically supported rotor

#This is a national stage application under 35 U.S.C. 371 of PCT application number PCT/US03/15155 having a May 15, 2003 international filing date and claims priority to U.S. patent application Ser. No. 10/007,803 filed Nov. 13, 2001, now U.S. Pat. No. 6,641,378.

#This invention relates to the field of pump design. In particular, this invention is drawn to bearings supporting pump impellers.

#Traditional dynamic pumps have a pumping component and a drive component. The pumping component includes an impeller supported by mechanical contact bearings. Mechanical energy is transferred from the drive component to the impeller of the pumping component through a shaft. A shaft seal in the pumping component permits rotation of the shaft while preventing leakage around the shaft.

#The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:

#FIG. 1 illustrates one embodiment of a centrifugal pump.

#FIG. 2 illustrates one embodiment of an impeller with a radial passive magnetic bearing (PMB).

#FIG. 1 illustrates one embodiment of a centrifugal pump 100 providing radial support for the impeller 110 through the use of magnetic bearings. The pump includes a top housing portion 120 and a bottom housing portion 130. When assembled the top and bottom housing portions define a volute pumping chamber 122. Rotation of impeller 110 drives the working fluid from the pump inlet 150 to the pump outlet 160.

#Centrifugal pump 100 utilizes an axial flux gap motor architecture. When assembled, the top and bottom housing portions serve as a motor stator. The motor windings 140 are disposed in the stator. The impeller serves as a motor rotor and includes a plurality of permanent magnets forming motor poles. The motor poles are arranged to co-operate with the motor windings to drive the impeller and thus achieve a pumping action. Back iron 170 serves to concentrate the flux generated by the windings 140.

#The pump further includes a spindle protruding from the base of the pumping chamber. The spindle is not illustrated in FIG. 1 to avoid obscuring the remainder of the pump. The impeller 110 rotates about the spindle. The spindle thus forms a part of the stator. In this embodiment, the impeller 110 contains one portion of the radial magnetic bearing. The spindle carries another portion of the radial magnetic bearing. The impeller and spindle bearing portions co-operate to provide radial support for the impeller.