| 摘要 |
An implantable rotary blood pump without a shaft seal. The pump includes a rotary element, having a pump impeller on one end. The impeller is specially designed with large, thick blades and tall, narrow blood channels, to minimize hemolysis. The rotary element and the impeller are maintained in radial alignment by respective, passive magnetic bearings. Axial restraint of the rotary element is provided by blood immersed thrust bearings, spaced a slight distance from either end of the rotor. Drive for the rotary element is provided by a structurally integrated, brushless electric motor. A plurality of permanent magnets is arranged in circular fashion within the impeller, constituting a rotor for the motor. The motor's stator includes circular windings of conductive wire, located within the pump housing and concentric with the rotor. With the stator energized, electromagnetic forces between the stator and the motor rotor cause the rotary element and the impeller to rotate. During operation, the rotary element shuttles back and forth along its axis between the thrust surfaces in response to heart pulsations. This bi-stable operation of the pump, allows fresh blood to flush through the thrust bearings in continuous fashion, minimizing the likelihood of thrombosis developing from operation of the pumps. |
