Abstract: Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, the pump apparatus includes a rotor having a bore, a ring-shaped upper rotor bearing magnet, and a ring-shaped lower rotor bearing magnet. The bearing magnets are concentric with the bore. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: An earpiece carrying a microphone and a transmitter is disclosed. The earpiece is adapted to position the microphone within a canal of an ear of a wearer.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, a pump housing has a spindle extending from a wall of the pump housing into a pumping chamber defined by the pump housing. The spindle has a stepped portion adjacent the wall. In one embodiment, the stepped portion is defined by a change in spindle diameter. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, a pump housing has a spindle extending from a wall of the pump housing into a pumping chamber defined by the pump housing. The spindle has a stepped portion adjacent the wall. In one embodiment, the stepped portion is defined by a change in spindle diameter. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: An apparatus includes a rotor, a stator, and a plurality of magnets forming bearing poles coupled to a selected one of the stator or the rotor. The apparatus further includes a plurality of shorted coils coupled to the other of the stator and the rotor. The plurality of bearing poles and shorted coils co-operate to form an electrodynamic bearing during rotation of the rotor. The electrodynamic bearing supports the rotor either axially or radially during operation. Hydrodynamic bearing surfaces are provided for generating a hydrodynamic bearing between the rotor and stator. The plurality of magnets may comprise a plurality of distinct magnetic elements or a single element comprising a plurality of distinct magnetic domains. The plurality of distinct magnetic elements or domains may be arranged to form a Halbach array.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, the pump apparatus includes a rotor having a bore, a ring-shaped upper rotor bearing magnet, and a ring-shaped lower rotor bearing magnet. The bearing magnets are concentric with the bore. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage or the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. In one embodiment, a pump apparatus includes a pump housing defining a pumping chamber. The housing has a spindle extending into the pumping chamber. A spindle magnet assembly includes first and second magnets disposed within the spindle. The first and second magnets are arranged proximate each other with their respective magnetic vectors opposing each other. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Various “contactless” bearing mechanisms including hydrodynamic, hydrostatic, and magnetic bearings are provided for a rotary pump as alternatives to mechanical contact bearings. These design features may be combined. In one embodiment, the pump apparatus includes a rotor having a bore, a ring-shaped upper rotor bearing magnet, and a ring-shaped lower rotor bearing magnet. The bearing magnets are concentric with the bore. The lack of mechanical contact bearings enables longer life pump operation and less damage to working fluids such as blood.

Abstract: Methods and apparatus for controlling a polyphase motor in implantable medical device applications are provided. In one embodiment, the polyphase motor is a brushless DC motor. The back emf of a selected phase of the motor is sampled while a drive voltage of the selected phase is substantially zero. Various embodiments utilize sinusoidal or trapezoidal drive voltages. The sampled back emf provides an error signal indicative of the positional error of the rotor. In one embodiment, the sampled back emf is normalized with respect to a commanded angular velocity of the rotor to provide an error signal proportional only to the positional error of the motor rotor. The error signal is provided as feedback to control a frequency of the drive voltage. A speed control generates a speed control signal corresponding to a difference between a commanded angular velocity and an angular velocity inferred from the frequency of the drive voltage.

Abstract: A pump includes an impeller, a stator, and a plurality of magnets forming bearing poles coupled to a selected one of the stator or the impeller. The pump further includes a plurality of shorted coils coupled to the other of the stator and the impeller. The plurality of bearing poles and shorted coils co-operate to form an electrodynamic bearing during rotation of the impeller. The electrodynamic bearing supports the impeller either axially or radially during operation of the pump. Hydrodynamic bearing surfaces are provided for generating a hydrodynamic bearing between the impeller and stator. The plurality of magnets may comprise a plurality of distinct magnetic elements or a single element comprising a plurality of distinct magnetic domains. The plurality of distinct magnetic elements or domains may be arranged to form a Halbach array.

Abstract: A pump includes an impeller, a stator, and a plurality of magnets forming bearing poles coupled to a selected one of the stator or the impeller. The pump further includes a plurality of shorted coils coupled to the other of the stator and the impeller. The plurality of bearing poles and shorted coils co-operate to form an electrodynamic bearing during rotation of the impeller. The electrodynamic bearing supports the impeller either axially or radially during operation of the pump. Hydrodynamic bearing surfaces are provided for generating a hydrodynamic bearing between the impeller and stator. The plurality of magnets may comprise a plurality of distinct magnetic elements or a single element comprising a plurality of distinct magnetic domains. The plurality of distinct magnetic elements or domains may be arranged to form a Halbach array.

Abstract: A pump includes an impeller, a stator, and a plurality of permanent magnets forming bearing poles coupled to a selected one of the stator or the impeller. The pump further includes a plurality of shorted coils coupled to the other of the stator and the impeller. The plurality of bearing poles and shorted coils co-operate to form an electrodynamic bearing during rotation of the impeller. The electrodynamic bearing supports the impeller either axially or radially during operation of the pump. Currents induced into each coil by a single bearing pole or by a plurality of bearing poles substantially simultaneously produce an electrodynamically generated magnetic field that repels the inducing bearing pole(s) when the impeller is rotating.