Electromechanical actuator

An electromechanical actuator comprising:

• a first electric motor;
• a first motion conversion mechanism;
• a second motion conversion mechanism;
• and
• a rotation restriction mechanism for the second motion conversion mechanism, wherein:
• the first motion conversion mechanism includes a first screw and a first nut that is fastened to the first screw;
• the second motion conversion mechanism includes a second screw and a second nut that is fastened to the second screw;
• the first motion conversion mechanism includes
• a first member that includes one of the first screw and the first nut, the first member being rotated by an output of the first electric motor, and
• a second member that includes the other of the first screw and the first nut;
• the second motion conversion mechanism includes
• a third member that includes one of the second screw and the second nut, the third member being movable integrally with the first member, and
• a fourth member that includes the other of the second screw and the second nut;
• and
• the rotation restriction mechanism is configured to be capable of selectively performing
• an operation that restricts rotation of the fourth member when the third member moves, and
• an operation that allows rotation of the fourth member when the third member moves.