Abstract: A damped double flywheel, in particular for a motor vehicle, comprises two coaxial inertia masses which are mounted for rotation with respect to each other against the action of springs and a viscous damper. The viscous damper comprises a sealed cavity bounded by two cover plates which are joined together through a spacer element. The viscous damper also includes first teeth directed radially inwards and alternating with second teeth which are directed radially outwardly.At least one of the cover members is provided with a recess in the face of the cover member which cooperates with the said second teeth, with the recess facing the latter and being so positioned as to lie against the corresponding tooth during normal operation, but not when the engine is being started or stopped, so that the viscous damper can operate to full effect under these latter conditions.

Abstract: A damped double flywheel comprises two coaxial inertia masses which are mounted for relative rotation, both against the action of a first series of springs and against the action of a viscous damping means. A damper wheel connects the viscous damping means with the first series of springs, and the latter couple the damper wheel with a first damping control means carried by the first mass. A second series of circumferentially acting springs, of greater stiffness than the first series of springs, couples the damper wheel to a second damping control means which is carried in rotation on the second mass.