US Patent 11187042 Curved piston liner and integral pad assembly

A rotary steerable tool for steering a drill string may include a tool collar extending along a longitudinal axis of the tool, a pad pusher, a pad retention housing, and a piston liner. The pad pusher may be rotatable about a pivot axis thereof between retracted and extended positions relative to the tool collar, for steering the drill string. The piston liner may be coupled to the pad retention housing and have a piston channel that defines a curved profile. The piston liner may provide sealing contact against a perimeter of the piston upon pivoting of the pad pusher through the piston channel along the curved profile, relative to the piston liner.