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Hydraulic Rotary Motor

IP.com Disclosure Number: IPCOM000045169D
Original Publication Date: 1983-Feb-01
Included in the Prior Art Database: 2005-Feb-06

Publishing Venue


Related People

Cummins, AW Majewski, FT Kaenel Von, W [+details]


A hydraulic rotary actuator was initially designed for use in a robot since none of the commercially available actuators could provide the servo response required. The design differed from those commercially available in that the internal seals were eliminated. Since the seals were eliminated, it became necessary to manufacture the stator, rotor and inside diameter of the unit to extremely close tolerances. It was assumed that the friction of the seals against the inner bore as affecting the servo response time. Ball bearings were used to support the rotor shaft against the side loads. Since the actuator functions in an oscillating motion, instead of a continuous rotating motion, flat spots were being worn on the balls of the ball bearing, compounding the tolerance problem.