Patent attributes
An electro-hydraulic linear lead screw actuator preferably includes an electric motor device, a hydraulic tube, an actuator lead screw, an actuator screw nut, an actuator rod and at least one external hydraulic flow passage. The actuator lead screw is rotated by the electric motor device. The actuator screw nut preferably includes a piston portion, a first screw nut portion and a second screw nut portion. A lead screw thread is formed through the first and second screw nut portions to threadably receive the actuator lead screw. The actuator rod is retained on the piston portion. Rotation of the electric motor device 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. At least one external hydraulic flow passage transfers hydraulic fluid between the first and second chambers.
