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US 11,639,747 B2Granted
Linear actuator
AssigneeGoodrich Actuation Systems Limited
InventorStephen Davies
Life of this patent
Estimating the term…
Abstract
A linear actuator includes a screw shaft comprising a screw thread and having a longitudinal axis A, a nut movable along the screw shaft from a retracted position to an extended position, and a plurality of rollers movable with the nut. Each roller includes a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the flank(s) so that the nut translates in an axial direction along the screw shaft. The screw thread has a variable lead angle. The actuator can be part of a power door opening system of an aircraft.
Claims12
A power door operating system of an aircraft comprising:
- a linear actuator, wherein the linear actuator is configured to actuate a component and includes:
- a screw shaft comprising a screw thread and having a longitudinal axis (A);
- a nut movable along the screw shaft from a retracted position to an extended position;
- and
- a plurality of rollers movable with the nut, each comprising a cylindrical surface configured to roll along one or more flanks of the screw thread, such that rotation of the screw shaft causes the rollers to roll along the one or more flanks so that the nut translates in an axial direction along the screw shaft;
- wherein the screw thread comprises one or more detents configured to lock the nut in one or more axial positions and the rollers rotate about a roller axis, wherein the roller axis of each of the rollers is at a non-perpendicular angle relative to the longitudinal axis of the screw shaft, the non-perpendicular angle being the same for each roller, and a compressive force exerted on the linear actuator by the component of the power door system pushes the cylindrical surface of each of the rollers against the one or more flanks, and
- wherein the component of the power door operating system is configured to exert the compressive force on the linear actuator in the direction of the longitudinal axis, wherein the compressive force always acts in the direction of the longitudinal axis throughout an entire range of movement of the linear actuator, and is such that when the nut is fully retracted the compressive force is at a minimum and when the nut is fully extended the compressive force is at a maximum, and the one or more detents are configured to prevent the compressive force from retracting the nut;
- wherein the rollers are all slanted in the same direction towards the longitudinal axis of the linear actuator;
- wherein the screw thread has a variable lead angle.
6 more elements
A power door operating system of an aircraft comprising:
- a linear actuator, wherein the linear actuator is configured to actuate a component and comprises:
- a screw shaft comprising a screw thread and having a longitudinal axis (A);
- a nut movable along the screw shaft from a retracted position to an extended position;
- and
- a plurality of rollers movable with the nut, each comprising a cylindrical surface and being configured to roll along the respective flank of the screw thread, such that rotation of the screw shaft causes the rollers to roll along a respective flank so that the nut translates in an axial direction along the screw shaft, and a compressive force exerted on the linear actuator by the component of the power door system pushes the cylindrical surface of each of the rollers against the respective flank;
- wherein the component of the power door operating system is configured to exert the compressive force on the linear actuator in the direction of the longitudinal axis, wherein the compressive force always acts in the direction of the longitudinal axis throughout an entire range of movement of the linear actuator, and is such that when the nut is fully retracted the compressive force is at a minimum and when the nut is fully extended the compressive force is at a maximum,
- wherein the screw thread has a variable lead angle, the screw thread nearest a first end of the screw shaft has a first lead angle, the screw thread nearest a second, opposite end of the screw shaft has a second lead angle, wherein the rollers roll along the first end of the screw shaft when the nut is in the retracted position and the rollers roll along the second end of the screw shaft when the nut is in the extended position, and the first lead angle is larger than the second lead angle.
4 more elements
Dependencies are inferred from the claim text.