SHAPE MEMORY ALLOY ACTUATOR WITH ENHANCED HEAT TRANSFER CHARACTERISTICS

摘要

A shape memory alloy (SMA) actuator includes an SMA element and a flexible outer coating or layer. The element is respectively activated by a heating source. The layer surrounds the element, and enhances the heat transfer characteristics of the element to increase the speed of the actuation cycle. The nominal geometry and/or thermal conductivity may be altered during an activation phase, and may include discrete elements oriented with respect to the element, and partially embedded in the layer. An end gripper assembly may be used to cause the layer to move in concert with the element during a phase transformation. An electro-mechanical system includes the cooling source and the actuator. A method includes connecting the actuator to a load, activating the element using the heating source, and deactivating the element using a cooling source or free/ambient air.