Patent attributes
Steering mechanisms for use in RSS systems may be devoid of an elastomeric piston seal. Pistons of the steering mechanisms have a convex cross-section that permit the piston to pivot along with a steering pad while moving laterally or radially along a piston axis defined by a piston bore. Hydraulic pressure may be maintained as the pad is extended since a limited gap size between the piston and the bore may be maintained throughout the motion of the pistons. The pistons may be retained to the steering pad in a T-slot and may be elongated in a direction orthogonal to the axis of the piston bore. A groove may be provided around the piston for a receiving a back-up seal therein. The back-up seal may include wear resistant balls embedded in a matrix, and balls may be preloaded to serve as flow restrictors even when worn.
