| 摘要 |
A method for actuating a member made of shape memory alloy, including stressing the shape memory alloy member so that its Ms point becomes positioned between its As point and its Af point, and applying a pulsed supply of electricity to it to heat it up is disclosed. The voltage and the duty factor d of the pulsed supply of electricity ensure that the relations theta ha greater than - theta ca and "d" less than or equal to theta cc/( theta cc - theta hb ) are satisfied, where theta ha is the heating speed of the shape memory alloy member in the region below its As point, theta hb is the heating speed of the shape memory alloy member in the region between its As point and its Af point, theta cc is the cooling speed of the shape memory alloy member in the region above its Ms point, and theta ca is the cooling speed of the shape memory alloy member in the region below its Mf point. Thereby, the shape memory alloy member is heated in an even, smooth, and controlled fashion for its actuation, so that there is substantially no risk of overheating of any of its parts during actuation, because large temperature differentials are not produced in the member. Thus, the service life of the member is kept long, because substantially no damage is engendered to its alloy material, since its temperature is kept stabilized near the transformation point. A device for practicing thus method is also described.
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