Conical rotary actuator and its application to the control of a rudder

A rotary actuator comprising an inner body and at least one outer body fitted coaxially in one another, at least one annular space defined between said inner and outer bodies, first blades integral with the inner body, second blades integral with the outer body, said first and second blades being arranged in an alternating manner in said annular space to define alternating first and second variable volume control chambers with different fluid tight control chambers being formed within said annular space, whereby an alternate pressurization of said first and second control chambers controls a relative rotation between the inner and outer bodies, wherein at least one of the inner and outer bodies has a variable cross-section, and each of the first and second blades has an approximately triangular shape, with a height decreasing from one end to the other;

• wherein the at least one outer body comprises two outer bodies fitted coaxially on two portions of the inner body, each one of said two portions carrying a set of said approximately triangular shaped first blades, and each outer body carrying a set of said approximately triangular shaped second blades which are arranged in an alternating manner with one of said set of first blades.

An aircraft control surface, comprising at least one panel, articulated to a rear spar of an aircraft wing element, about an articulation axis substantially parallel to said rear spar, and pivoting control means for controlling pivoting of the at least one panel about said articulation axis, wherein said pivoting control means includes at least one rotary actuator comprising an inner body and at least one outer body fitted coaxially in one another, at least one annular space defined between the inner and outer bodies, first blades integral with the inner body and second blades integral with the outer body, the first and second blades being arranged in an alternating manner in said annular space to define alternating first and second variable volume fluid tight control chambers within said annular space, whereby an alternate pressurization of said first and second control chambers controls a relative rotation between the inner and outer bodies, wherein at least one of the inner and outer bodies provide a variable cross-section, each of the first and second blades having an approximately triangular shape, with a height decreasing from one end to the other.