Patent ID: 9211368
Filing Date: 2015-12-15
Classification: A61M

Abstract:
1. A heart assist device, comprising: a rotary pump housing having a cylindrical bore, a pumping chamber and a motor stator including an electrically conductive coil located within said housing and surrounding a portion of said cylindrical bore, and also comprising a rotor, said rotor having a cylindrical shaft with an outer surface and at least one impeller appended to one end of said shaft; wherein said rotor comprises a plurality of magnets located within said shaft and opposite said motor stator; wherein said bore is closely fitted to the outer surface of said shaft forming a journal bearing comprising hydrodynamic journal bearing; wherein when said rotor is positioned and rotates within said bore, said at least one impeller is positioned and rotates within the pumping chamber; wherein said pumping chamber and said journal bearing are connected by a leak path to allow blood to pass between the pumping chamber into the journal bearing; wherein said rotor is suspended in the radial direction within said housing substantially by hydrodynamic thrust forces generated by relative movement of said rotor with respect to and within said pump housing; and wherein said shaft flares at an end longitudinally opposed to said impeller thereby forming a radial projection over at least a portion of said bore of said housing, said projection forming a hydrodynamic thrust bearing at the bore end portion for opposing axial thrusting of the rotor.