Aircraft landing gear comprising a main damper and an anti-shimmy secondary damper
Aircraft landing gear ( 1 ) comprising: an axle shaft ( 2 ); a strut ( 3 ) extending along a main strut axis (Z) and having a first part ( 3 a ) carrying the said axle shaft ( 2 ) and a second part ( 3 b ); a main damper ( 5 ) designed to damp axial movements of the first strut part ( 3 a ) with respect to the second strut part ( 3 b ); a first secondary damper ( 6 a ) distinct from the said main damper and designed to damp a movement of angular oscillation, about the axis (Z). The first secondary damper ( 6 a ) is carried by the first strut part ( 3 a ) and comprises: an inertial mass (M); and means ( 7 a ) of connecting the inertial mass (M) to the first strut part ( 3 a ) which means are designed to damp rotational movements of this inertial mass (M) about the axis (Z).
1. An aircraft landing gear ( 1 ) comprising:
an axle shaft ( 2 ) designed to carry at least one wheel via which the aircraft runs along the ground;
a strut ( 3 ) extending along a main strut axis (Z) and having a first part ( 3 a ) carrying the said axle shaft ( 2 ) and a second part ( 3 b ) designed to be connected to a bearing structure belonging to the aircraft, the said main strut axis (Z) passing through these first and second strut parts ( 3 a , 3 b );
a main damper ( 5 ) designed to damp axial movements of the first strut part ( 3 a ) with respect to the second strut part ( 3 b );
a first secondary damper ( 6 a ) distinct from the said main damper and designed to damp a movement of angular oscillation, about the main strut axis (Z), of the first strut part ( 3 a ) with respect to the second strut part ( 3 b ),
characterized in that the said first secondary damper ( 6 a ) is wholly carried by the first strut part ( 3 a ) alone, this first secondary damper ( 6 a ) comprising:
an inertial mass (M); and
connecting means ( 7 a ) connecting this inertial mass (M) to the first strut part ( 3 a ), these connecting means ( 7 a ) being designed to damp at least rotational movements of this inertial mass (M) with respect to the first strut part ( 3 a ) and about the main strut axis (Z).
2. The aircraft landing gear according to claim 1 , further comprising a first rim ( 10 ) for supporting a first wheel on which the aircraft runs and a second rim for supporting a second wheel on which the aircraft runs, these first and second rims being mounted for rotation about the axle shaft ( 2 ), the first secondary damper ( 6 a ) being mounted between the first and second rims ( 10 , 20 ).
3. The aircraft landing gear according to claim 2 , in which the first secondary damper ( 6 a ) is at least partially arranged inside a hollow zone ( 10 a ) of the first rim ( 10 ) and inside a hollow zone ( 20 a ) of the second rim ( 20 ).
4. The aircraft landing gear according to claim 1 , in which the inertial mass of the first secondary damper ( 6 a ) is in the shape of a ring ( 14 ) and extends around the said first strut part ( 3 a ).
5. The aircraft landing gear according to claim 1 , in which the connecting means ( 7 a ) which connect the inertial mass (M) of the first secondary damper ( 6 a ) to the first strut part ( 3 a ) comprise an arm ( 22 ) extending radially with respect to the said main strut axis (Z) and carrying this inertial mass (M) at one of its ends.
6. The aircraft landing gear according to claim 1 , in which the said connecting means ( 7 a ) designed to connect the said inertial mass (M) of the said first secondary damper ( 6 a ) to the said first strut part comprise a first fixing ring ( 12 ) secured to and around the said first strut part and an elastic annular sleeve ( 13 ) concentric with the said main strut axis (Z), this elastic annular sleeve extending all around the first fixing ring ( 12 ).
7. The aircraft landing gear according to claim 1 , in which the said connecting means ( 7 a ) connecting the said inertial mass (M) to the first strut part ( 3 a ) comprise:
elastic return means ( 8 a ) returning the inertial mass (M) towards a fixed rest position of the inertial mass with respect to the axle shaft ( 2 ); and
damping means ( 9 a ) which have a damping coefficient of predetermined value.
8. The aircraft landing gear according to claim 7 , in which the said elastic return means ( 8 a ) have a value of angular stiffness of the inertial mass (M) in rotation about the main strut axis (Z) and with respect to the first strut part ( 3 a ) which is constant.
9. The aircraft landing gear according to claim 1 , in which the said first strut part ( 3 a ) carries a second secondary damper ( 6 b ) distinct from the said first secondary damper ( 6 a ), this second secondary damper ( 6 b ) comprising:
a second inertial mass; and
second connecting means connecting this second inertial mass to the said first strut part ( 3 a ), these second connecting means being designed to damp rotational movements of this second inertial mass (M) about the strut axis (Z) and with respect to the said first strut part ( 3 a ).
10. The aircraft landing gear according to claim 9 , in which the second inertial mass of the second secondary damper ( 6 b ) is in the shape of a ring ( 14 ) and extends around the said first strut part ( 3 a ).