Ball screw rotary actuator with independent ball paths
AssigneeThe Boeing Company
InventorMitchell Loren Ray Mellor
Life of this patent
Estimating the term…
Abstract
Ball screw rotary actuator with independent ball paths. In one embodiment, a ball screw rotary actuator includes an outer cylinder including a fluid port, a piston configured to translate within the outer cylinder due to fluid pressure, helical grooves disposed between the outer cylinder and the piston, and outer ball bearings configured to travel in the helical grooves to rotate the piston within the outer cylinder as the piston translates. The ball screw rotary actuator also includes an inner shaft situated radially inward of the piston, straight grooves disposed between the piston and the inner shaft, and inner ball bearings configured to travel in the straight grooves, and to rotate the inner shaft as the piston rotates.
Claims20
A ball screw rotary actuator, comprising:
- an outer cylinder including a fluid port;
- a piston configured to translate within the outer cylinder due to fluid pressure;
- helical grooves disposed between the outer cylinder and the piston;
- outer ball bearings configured to travel in the helical grooves to rotate the piston within the outer cylinder as the piston translates;
- an inner shaft situated radially inward of the piston;
- straight grooves disposed between the piston and the inner shaft;
- and
- inner ball bearings configured to travel in the straight grooves, and to rotate the inner shaft as the piston rotates.
A method of assembling a ball screw rotary actuator, the method comprising:
- providing a piston to translate within an outer cylinder due to fluid pressure;
- forming helical grooves around an outer diameter of the piston;
- providing an inner shaft radially inward of the piston;
- forming straight grooves between the inner shaft and the piston;
- inserting outer ball bearings into the helical grooves to force rotation of the piston with respect to the outer cylinder as the piston translates due to the fluid pressure;
- and
- inserting inner ball bearings into the straight grooves to force rotation of the inner shaft with the rotation of the piston.
An aircraft, comprising:
- a fuselage;
- a wing projecting from the fuselage;
- a flight control surface connected to the wing via a joint;
- and
- a ball screw rotary actuator connected to the joint and configured to rotate the flight control surface with respect to the wing, the ball screw rotary actuator comprising:
- an outer cylinder including a fluid port;
- a piston configured to translate within the outer cylinder due to fluid pressure;
- helical grooves disposed between the outer cylinder and the piston;
- outer ball bearings configured to travel in the helical grooves to rotate the piston within the outer cylinder as the piston translates;
- an inner shaft situated radially inward of the piston;
- straight grooves disposed between the piston and the inner shaft;
- and
- inner ball bearings configured to travel in the straight grooves, and to rotate the inner shaft as the piston rotates.
Dependencies are inferred from the claim text.