Electromechanical pitch actuation system for a turbomachine propeller

A pitch actuation system for a turbine engine propeller, comprising an actuator, a main transmission screw which is configured to be connected to blades of the propeller so as to rotate the blades relative to a blade pitch axes (B), characterised in that the actuator is an electromechanical actuator comprising:

• the main transmission screw that can move with a degree of rotational freedom and a degree of translational freedom along a longitudinal axis (A);
• a main nut, through which said main transmission screw passes and which cooperates with the main transmission screw so as to translationally displace along the axis (A);
• a decoupling means configured so that a translational displacement of the main nut causes a modification to the pitch of the propeller blades but so that a rotational displacement of the propeller does not cause a rotational displacement of the main nut, the decoupling means comprising a ring surrounding the main nut and a first rolling bearing mounted between the ring and the main nut, the decoupling means comprising a second rolling bearing mounted between the ring and an element configured to be connected to the blades;
• a blade pitch control means mounted in a first rotationally locked housing, which means comprise at least one electric motor for driving a first rotor about the axis (A), and a first component set into rotation about the axis (A) by said first rotor by means of a first planet reduction gear, the pitch actuation system being configured to move the main transmission screw in a first degree of freedom from a rotation of said first component;
• a feathering means, which comprise at least one second electric motor for driving a second rotor about the axis (A), the pitch actuation system being configured to move the main transmission screw in a second degree of freedom when said at least one second electric motor is activated and to block said movement when said second electric motor is not activated,
• and in that said first planet reduction gear comprises a ring gear rigidly connected to said first component, a planet shaft rigidly connected to said first rotor and a planet carrier rigidly connected to said first housing, so as to block the rotation of the ring gear, and thus of the first component, in the event that an axial force absorption bearing is blocked in the blade pitch control means.