无源磁浮人工心脏泵的改进型设计

磁力轴承没有机械接触，机械旋转泵应用磁力轴承后就可以解决机械磨损及轴承处产生血栓的问题，但是，国外使用的磁力轴承均是电磁铁加位置测量及反馈控制，不仅结构复杂，体积大，而且消耗附加电能，整个系统的可靠性也差，作者探索用永久磁铁制作磁力轴承，研制成改进型无源磁浮叶轮泵，泵的转子径向由永磁体磁力支承，转子的一端紧固着叶轮，另一端镶嵌磁钢；与转子磁钢相对，驱动电机线圈产生旋转磁场，驱动转子旋转，在实验室用生理盐水试验，当转子静止或低于4000rpm旋转时，转子磁钢在轴向同位于转子和定子之间的隔板有一点接触，接触点位于转子的轴线上，当转子转速逐渐增加至4000rpm以上，转子在轴向与定子脱离，从而实现完全磁浮，由于转子轴向磁浮由液动力产生，且转子磁钢有陀螺效应，所以转子在浮起的过程中运转非常平稳，当用作左心室辅助装置时，叶轮血泵工作转速范围在5000-8000rpm之间，所以实用时转子完全磁浮是不成问题的，无源磁浮技术是对Earnshaw理论（1842）及Braunbeck推论（1939）的重大补充，将在其它科技领域得到广泛应用。

Improved Design of Permanent Maglev Impeller Assist Heart

Magnetic bearing has no mechanical contact between the rotor and stator. And a rotary pump with magnetic bearing has therefore no mechanical wear and thrombosis due to bearing. The available magnetic bearings, however, are devised with electric magnets, need complicated control and remarkable energy consumption. Resultantly, it is difficult to apply an electric magnetic bearing to rotary pump without disturbing its simplicity, implantability and reliability. The authors have developed a levitated impeller pump merely with permanent magnets. The rotor is supported by permanent magnetic forces radially. On one side of the rotor, the impeller is fixed; and on the other side of the rotor, the driven magnets are mounted. Opposite to this driven magnets, a driving motor coil with iron corn magnets is fastened to the motor axis. Thereafter, the motor drives the rotor via a rotating magnetic field. By laboratory tests with saline, if the rotor stands still or rotates under 4 000 rpm, the rotor has one-point contact axially with the driving motor coil. The contacting point is located in the center of the rotor. As the rotating speed increases gradually to more than 4 000 rpm, the rotor will detache from the stator axially. Then the rotor will be fully levitated. Since the axial levitation is produced by hydraulic force and the driven magnets have a gyro-effect, the rotor rotates very steadly during levitation. As a left ventricular assist device, the pump works in a rotating speed range of 5 000-8 000 rpm, the levitation of the impeller hence is ensured by practical use of the pump.