Development of Lorentz Force Type Tilt Control Motor for Rotary Blood Pumps

摘要

Hydrodynamic beatings and magnetic bearings can provide significant advantages over traditional mechanical bearings for use in rotary blood pumps. These technologies can provide high performance and-physiological compatibility. A miniaturized and flattened Lorentz force type tilt-controllable motor has been developed to work in conjunction with a hydrodynamic bearing to permit stable levitation and rotation. The motor can rotate a rotor and control its tilt angle with an actuator. Two conducting wire tracks are set up on the stator to provide motor torque and tilt control torque respectively, while sixteen permanent magnets are placed in the rotor. Hall-effect sensors are used to measure rotational speed and rotational angle. The motor was fabricated and its rotation and tilt control performance were evaluated. The diameter and height of the prototype motor are 44 mm and 8 mm, respectively. The air gap between the stator conductor and the rotor is 1 mm. The results of torque measurement show that the motor can generate a rotational torque of 12.5 mNm at target speed 2600 rpm and a tilt control torque of 6 mNm with an excitation current of 2.5 A. Basic performance of the tilt control was obtained.