Antivibration suspension means for a tie bar of an aircraft power transmission gearbox, an antivibration suspension device, and an aircraft

1. Antivibration suspension means for a tie bar connecting a power transmission gearbox of an aircraft to a carrier structure, the suspension means comprising a lever extending from a distal end supporting at least one flyweight to a proximal end provided with first hinge means for hinging the lever to a carrier structure, the suspension means having a second hinge for hinging the tie bar to the lever, and including torsion return means fitted with a rotary actuator having an outlet shaft movable in rotation about a torsion axis (AXT), said outlet shaft being secured to said lever to generate torque on the lever proportional to its pivot angle, thereby imparting torsion stiffness to said first hinge, said suspension means including a computer controlling said actuator to adapt said torsion stiffness of the lever to the flight conditions of said aircraft.

2. Suspension means according to claim 1 , wherein said suspension means include means for measuring a speed of rotation of a lift rotor of said aircraft, said computer being connected to the measurement means in order to adapt said torsion stiffness as a function of said speed of rotation.

3. Suspension means according to claim 1 , wherein said suspension means include a measurement system for measuring vibration levels of said aircraft in order to adapt said torsion stiffness as a function of the measured vibration levels.

4. Suspension means according to claim 1 , wherein said first hinge comprises a pivot connection having a first pivot shaft directed along a first direction (AX 1 ), said first pivot shaft being inserted in a fitting suitable for being fastened to a carrier structure carrying said gearbox.

5. Suspension means according to claim 4 , wherein said outlet shaft is directed along said first direction (AX 1 ).

6. Suspension means according to claim 4 , wherein said first hinge includes said fitting co-operating with said first pivot axis (AX 1 ), and said fitting includes at least one stop for limiting the stroke of the lever.

7. Suspension means according to claim 1 , wherein said second hinge includes a ball joint having a second connection shaft directed along a second direction (AX 2 ).

8. Suspension means according to claim 7 , wherein said second direction (AX 2 ) is parallel to said outlet shaft.

9. An antivibration suspension device for a mechanical assembly having at least one lift rotor and a power transmission gearbox, the suspension device including at least three tie bars, each of the three tie bars being hinged via a top end to the gearbox and via a bottom end to suspension means, at least one suspension means including a lever extending from a distal end supporting at least one flyweight to a proximal end having a first hinge for hinging the lever to a carrier structure, the at least one suspension means having a second hinge for hinging a tie bar to the lever between said proximal end and a center of gravity (Cg) of the lever, the at least one suspension means including torsion return means having a rotary actuator with an outlet shaft movable in rotation about a torsion axis (AXT), said outlet shaft being secured to said lever to generate torque on said lever proportional to its pivot angle, thereby inducing torsion stiffness at said first hinge, said at least one suspension means including a computer controlling said actuator to adapt said torsion stiffness of the lever to flight conditions.

10. A suspension device according to claim 9 , wherein the computers of the suspension means are constituted together by a single computer controlling all of the actuators.

11. An aircraft having a carrier structure and a mechanical assembly including a lift rotor and a power transmission gearbox driving the lift rotor, wherein the aircraft includes a suspension device according to claim 9 .

12. Antivibration suspensi 0 on device for a tie bar connecting a power transmission gearbox of an aircraft to a carrier structure, the suspension device comprising a lever extending from a distal end supporting at least one flyweight to a proximal end provided with a first hinge for hinging the lever to a carrier structure, the suspension device having a second hinge for hinging the tie bar to the lever, and including a torsion return fitted with a rotary actuator having an outlet shaft movable in rotation about a torsion axis (AXT), the outlet shaft being secured to the lever to generate torque on the lever proportional to its pivot angle, thereby imparting torsion stiffness to the first hinge, the suspension device including a computer controlling the actuator to adapt the torsion stiffness of the lever to the flight conditions of the aircraft.

13. Suspension device according to claim 12 , wherein the suspension device includes a measurement device sensor for measuring a speed of rotation of a lift rotor of the aircraft, the computer being connected to the measurement device on order to adapt the torsion stiffness as a function of the speed of rotation.

14. Suspension device according to claim 12 , wherein the suspension device includes a measurement system for measuring vibration levels of the aircraft on order to adapt the torsion stiffness as a function of the measured vibration levels.

15. Suspension device according to claim 12 , wherein the first hinge comprises a pivot connection having a first pivot shaft directed along a first direction (AX 1 ), the first pivot shaft being inserted in a fitting suitable for being fastened to a carrier structure carrying the gearbox.

16. Suspension device according to claim 15 , wherein the outlet shaft is directed along the first direction (AX 1 ).

17. Suspension device according to claim 15 , wherein the first hinge includes the fitting co-operating with the first pivot axis (AX 1 ), and the fitting includes at least one stop for limiting the stroke of the lever.

18. Suspension device according to claim 12 , wherein the second hinge includes a ball joint having a second connection shaft directed along a second direction (AX 2 ).

19. Suspension device according to claim 18 , wherein the second direction (AX 2 ) is parallel to the outlet shaft.