The Boeing Company
Screw actuator, aircraft comprising a screw actuator, and method of lifting a load

Abstract:

A screw actuator, includes: a screw comprising a first helical contact surface and a first helical raceway surface; a nut comprising a second helical contact surface and a second helical raceway surface; and a plurality of ball bearings in a helical raceway formed by the first helical raceway surface and the second helical raceway surface. When the screw is loaded relative to the nut in a first axial direction, the first helical contact surface is compressed against the second helical contact surface. When the screw is loaded relative to the nut in a second axial direction, the plurality of ball bearings are compressed between the first helical raceway surface and the second helical raceway surface.