Patent ID: 8182382

Claim:
A pulley assembly for a start-stop belt drive, comprising a hub having an axis and designed to be connected to a crankshaft of an internal-combustion engine, a pulley designed to co-operate with a belt of a belt drive and supported in a rotatable way by said hub through a bearing, and a seismic mass connected to said hub so as to rotate with respect to said hub for defining a dynamic damping device for damping the torsional vibrations, said pulley assembly comprises a band clutch, which co-operates selectively between said hub and said pulley, the band clutch comprising a coil element and electromagnetic actuation means co-operating with said coil element and mobile between a coupling position in which said band clutch is closed and said hub is rotationally fixed to said pulley when said hub tends to overtake said pulley, and a position of decoupling in which said band clutch is open and said pulley turns idle on said hub and in that said band clutch is at least partially housed in a cavity defined by said hub in a position radially lower than that of said seismic mass.