Mixed flow artificial heart pump with axial self-bearing motor

With the objective of developing a small blood pump with a levitated rotor, we propose a design scheme for an axial-type self-bearing motor. The axial type motor, which is basically composed of a disc motor and an axial magnetic bearing, controls both the rotation and the axial translation of the rotor. The proposed motor is similar to the bidirectional disc motor, except for changing the magnitudes of both sides of the flux to control the axial attractive force. However, the radial and tilt directions rely on passive stability, and, therefore, the rotor has poor damping which might cause damage to blood constituents. The design includes a hydrodynamic bearing for improving radial support properties. Finally, to confirm its functionality, an experimental prototype of the proposed motor has been constructed and incorporated into a mixed flow blood pump. The results indicated that the bidirectional axial-type self-bearing motor had high efficiency as a small continuous flow blood pump, delivering sufficient flow rate and pressure head.