Shape memory alloy actuator system and method
AssigneeThe Boeing Company
InventorIan M. Gunter
Life of this patent
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Abstract
An actuator assembly may comprise a housing, a shaft, a shape memory alloy (SMA) torque tube, and first and second unidirectional bearings. The SMA torque tube may rotate the shaft. The first unidirectional bearing may limit rotation of the shaft relative to the SMA torque tube to a first direction. The second unidirectional bearing may prevent rotation of the shaft relative to the housing along a second direction opposite the first direction.
Claims19
An actuator system, comprising:
- a housing;
- a clutch having clutch plates and a clutch shaft, the clutch plates being axially engageable with one another causing the clutch shaft to be coupled to an output shaft;
- a shape memory alloy (SMA) torque tube for rotating the clutch shaft;
- a first unidirectional bearing limiting rotation of the clutch shaft relative to the SMA torque tube to a first direction;
- a second unidirectional bearing preventing rotation of the clutch shaft relative to the housing along a second direction opposite the first direction and
- an over-center linkage coupled to the clutch and configured to axially disengage the clutch plates.
An actuator system, comprising:
- a clutch having clutch plates and a clutch shaft;
- an over-center linkage;
- a shape memory alloy (SMA) linear actuator coupled to the over-center linkage and linearly contracting when heated causing locking of the over-center linkage and causing the clutch plates to axially engage with one another and causing the clutch shaft to be coupled to an output shaft;
- and
- an SMA ribbon coupled to the over-center linkage and linearly contracting when heated causing collapse of the over-center linkage and axial disengagement of the clutch plates from one another.
A method of rotating a shaft relative to a housing, comprising the steps of:
- coupling a clutch to an over-center linkage;
- axially engaging clutch plates of the clutch having a clutch shaft;
- coupling the clutch shaft to an output shaft in response to axially engaging the clutch plates;
- heating an SMA torque tube;
- twisting the SMA torque tube in response to heating thereof;
- rotating the output shaft in response to twisting the SMA torque tube;
- limiting rotation of the clutch shaft relative to the SMA torque tube to a first direction using a first unidirectional bearing;
- preventing rotation of the clutch shaft relative to the housing along a second direction opposite the first direction using a second unidirectional bearing;
- and
- disengaging the clutch plates using the over-center linkage.
A method of disengaging a clutch, comprising the steps of:
- coupling the clutch to an over-center linkage , the clutch having clutch plates being axially engaged to one another, the clutch plates being coupled to an output shaft;
- heating an SMA ribbon coupled to the over-center linkage;
- linearly contracting the SMA ribbon in response to the heating thereof;
- collapsing the over-center linkage in response to linearly contracting the SMA ribbon;
- and
- disengaging the clutch plates in response to collapsing the over-center linkage.
Dependencies are inferred from the claim text.