Pulley decoupler

Abstract

A decoupler is provided for rotationally driving a generator of an auxiliary-unit belt drive of an internal combustion engine, including: a pulley, a hub, and two bearing points, at which the pulley is rotatably supported on the hub, a series arrangement of a helical torsion spring and a one-way clutch, which allows the hub to overtake the pulley, and a spring plate, which is rotationally fixed in relation to the pulley or the hub, for the one spring end and a spring plate, which can be rotated in relation to the pulley and the hub, for the other spring end. The spring ends, which lie against ramp steps of the spring plates, radially expand the helical torsion spring as the driving torque is transmitted. The frictional torque, produced in one of the bearing points when the hub is overtaking, acts on the rotatable spring plate in a direction of rotation of the rotationally fixed spring plate. The other bearing point, according to the invention, has a part that is rotationally fixed in relation to the rotationally fixed spring plate, on which part the rotatable spring plate is supported, a further frictional torque thus being produced, which acts on the rotatable spring plate in the direction of rotation of the rotationally fixed spring plate.