人工括約筋への適用を想定した温度制御トランスの特性評価(生体磁気・医療応用)

概要

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The implant medical device discussed here is an artificial sphincter that utilizes shape memory alloy (SMA). This device is implanted into the body of a patient to provide independent evacuation for a patient using an artificial anus. The artificial sphincter operates based on the phase transformation of the SMA that occurs when it is heated. The phase transformation completion temperature of the SMA that we used is 55℃. To prevent the SMA from being overheated in a living body, a transformer utilizing thermosensitive ferrite is used as a temperature control device. In an earlier prototype, we confirmed that temperature control of the SMA was possible. We examined suitable core design and composition. The transformer core type is composed of a hybrid core that uses thermosensitive Ni-Cu-Zn ferrite (Curie-point Tc = 60℃) and non-thermosensitive Mn-Zn ferrite. Effective saturation magnetic flux density of the thermosensitive ferrite and the Mn-Zn ferrite are 250 mT and 520 mT respectively at room temperature. Class 10 W power transmission is possible through this small transformer. When the temperature of the SMA is higher than Tc, magnetization of the thermosensitive ferrite disappears and power transmission to the heater weakens.
社団法人日本磁気学会の論文
2004-05-01