Mobile member of a turbomachine which comprises means for changing the resonance frequency of same

1. A rotor of an aircraft turbomachine having a main axis A, which comprises means for modifying a critical speed of the rotor between a first critical speed and a second critical speed, depending on whether the rotational speed of the rotor is lower or higher than a predefined rotational speed between the first critical speed and the second critical speed,

said means for modifying the critical speed of the rotor comprising:

a component that is capable of occupying a first state or a second state depending on whether the rotational speed of the rotor is lower or higher than the predefined rotational speed, each state of the component corresponding to a critical speed of the rotor, and

means for driving the component towards one or the other of the two states thereof, depending on the rotational speed of the rotor,

wherein the means for modifying the critical speed of the rotor further comprise a component that engages with the drive means and is capable of being deformed elastically between one or the other of two stable forms, each of which corresponding to a state of said component.

2. The rotor according to claim 1 , wherein the component consists of a system such as a flexible, inverted cage, providing flexibility or not to the means for modifying the critical speed of the rotor, depending on whether it is in one or the other of the two operating states thereof.

3. The rotor according to claim 1 , wherein the drive means comprise at least one actuating member, which is movably mounted and is capable of moving radially under a centrifugal effect when the rotational speed of the rotor is higher than said predefined rotational speed.

4. The rotor according to claim 1 , wherein the drive means comprise an insert capable of moving along the main axis of the rotor and which is capable of being coupled with the component in order to change the state of the component.

5. The rotor according to claim 4 , wherein the drive means comprise means for transforming the radial movement of the actuating member into an axial movement of the insert.

6. The rotor according to claim 5 , wherein the means for transforming the radial movement of the actuating member comprise two revolving portions facing each other and mobile in relation to each other, between which the actuating member is positioned and in that the support surfaces of the revolving portions facing each other are inclined in relation to each other.

7. The rotor according to claim 4 , wherein the drive means comprise elastic means for driving the insert towards a position corresponding to the state of the component associated with a rotational speed of the rotor that is below the predefined rotational speed.

8. The rotor according to claim 4 , wherein the drive means comprise a main radial orientation wall that is axially convex and linked to the insert, and in that said convex wall is elastically deformable and capable of occupying two stable forms distributed on either side of a radial plane, passing through a radially outer edge of the convex wall.

9. The rotor according to claim 1 , wherein the means for changing the critical speed of the rotor are produced such that they reduce the critical speed of the rotor when the rotational speed of the rotor is higher than the predefined rotational speed and such that they increase the critical speed of the rotor when the rotational speed of the rotor is lower than the predefined rotational speed.

10. An aircraft turbomachine comprising a rotor according to claim 1 , which is equipped with means capable of modifying the critical speed of the rotor when the rotational speed of the rotor is higher or lower than a predefined rotational speed.