Patent attributes
An electro-hydraulic linear ball screw actuator preferably includes an electric motor, a hydraulic tube, an actuator ball screw, a ball nut device, an actuator rod and at least one external hydraulic flow passage. The actuator ball screw is rotated by the electric motor. The ball nut device includes a ball nut base, a piston portion and a rod thread. The ball nut device is retained in the hydraulic tube. The ball nut base includes a plurality of ball bearings, which engage ball threads on the actuator ball screw. The actuator rod is retained on the piston portion. Rotation of the electric motor causes the actuator rod to extend or retract. A first hydraulic chamber is located behind the piston portion and a second hydraulic chamber is located in front of the piston portion. The at least one external hydraulic flow passage transfers hydraulic fluid between the first and second chambers.
