Vibration filter for a transmission with automatic, continuous or discontinuous, gearchange, especially for a motor vehicle

In a vibration filter for a transmission with automatic gear changing for a motor vehicle, including a torsion damper disposed between an input or driving element arranged to be driven in rotation by the crankshaft of the motor vehicle engine, and an output or driven shaft arranged to be coupled to an input shaft or driven shaft of the transmission, the torsion damper includes elastic means: the stiffness of the damper is variable and is obtained by virtue of the said elastic means, which are in the form of helical springs oriented substantially radially; the input element is a primary flywheel ( 10 ) which has at its radially inner periphery an axial flange ( 12 ) for supporting a bearing ( 13 ) which centres and guides in rotation a secondary inertial flywheel ( 20 ) constituting the output element.