本論文的主要目的是探討磁浮軸承在軸流式心室輔助器之應用與輔助器中的無刷 直流馬達設計。目前較常見的心室輔助器是利用傳統軸承做為轉子的支撐結構， 但易造成某部分的血液流速為零，而形成血栓，通常皆是累積在軸承處，不僅會 使得血管堵塞，也會造成輔助器的損壞，故發展無接觸的磁浮軸承輔助器是必要 的。在一般磁浮系統中，被動式磁浮軸承是以兩平行的磁石做相斥或相吸的動作 ，所以只有軸向或徑向會平衡，導致當主動式磁浮系統失效時，轉子會失去平衡 ，而撞上管壁，所以本論文提出另一種形式的被動式磁浮結構，使軸向和徑向可 以暫時穩定，並利用Ansoft公司的RMXpot來設計輔助器中的無刷直流馬達。 The main objection of the paper is to describe the development of a magnetically axial ventricular assist device. In recently, the usually seen types of the ventricular assist devices use traditional bearing as the supporting structure. However, this structure might cease the flow velocity of blood in some parts of the assist device to zero and cause thrombus, especially in bearings. The thrombus may not only cause the blood vessel obstruction, but also damage the assist device. Because of these disadvantages, there is a trend to develop the magnetically suspending ventricular assist device. In present magnetically suspending systems, a passive system is used to maintain the radial or axial balance of the rotor of the assist device only. While the active magnetic bearing system is failure, the rotor of the assist device would lose the balance and strike the stator of the assist device. This paper provides a new passive magnetic bearing system which maintains both of the radial and axial transient balance of the rotor in assist device. Also, this paper use the motor design software, RMxprt by Ansoft, to design a blushless dc motor used in the assist device.