A decoupler
assembly (20) is provided for transferring rotational torque between a
drive shaft (16) and a drive belt (18) of an
automotive engine. The decoupler
assembly includes a drive hub (40) configured to be fixedly secured to the
drive shaft. A
pulley (22) is rotatably coupled to the drive hub (40) and adapted to be drivingly engaged with the belt (18). A spring shell (70, 100) is operatively coupled between the drive hub and the
pulley for selective rotation therewith and a biasing member (130) is operatively coupled between the spring shell and the drive hub for isolating oscillatory vibrations between the drive hub and the
pulley caused by rotation of the
drive shaft. A
clutch element (140) is seated between the spring shell (70, 100) and the pulley (22) for selectively transferring rotational torque from the drive hub to the pulley. The pulley (22) includes an inner
clutch surface (26) and the
clutch element includes a plurality of coils in frictional engagement with the inner clutch surface and an end coupled to the spring shell for expanding the coils against the inner clutch surface upon rotation of the spring shell with the drive hub to selectively transfer torque between the drive hub (40) and the pulley (22).