Rotary actuator with external bearings

Abstract

A fluid-powered rotary actuator having a body adapted for coupling to a movable member to transfer rotational force thereto. A drive member includes a flange extending axially outward from a body first end, and a stub shaft extending coaxially within the body toward a body second end. The flange includes first, second and intermediate portions, with the first portion axially outward of the second portion. The second portion has a ball race, the first portion is threaded, and the intermediate portion has straight splines formed thereon. The drive member has an elongated aperture, and first and second fluid conduits formed therein. A fluid-transfer tube is carried by a piston and extends into the central aperture. Pressurized fluid applied to a flange first port is communicated through the first fluid conduit to a first piston side, and pressurized fluid applied to a flange second port is communicated through the second fluid conduit via the transfer tube to a second piston side. A mounting member is adapted for coupling to a support frame to transfer rotational force thereto. The mounting member has an aperture with straight splines which mesh with the intermediate portion straight splines to permit adjusting longitudinal movement of the mounting member relative to the flange while holding the flange stationary against rotation relative to the support frame.