Abstract: A sheave which can be used to transmit motion to belts or chains or as an inertial damper has an input element which can be driven by the output shaft of an internal combustion engine in a motor vehicle, an output element which is rotatable relative to the input element and can drive one or more belts or chains to transmit motion to one or more fans, pumps and/or other aggregates in a motor vehicle, and a damping unit which is installed between the input and output elements in an annular chamber defined by a housing which forms part of the input element and/or the output element. The damping unit employs long arcuate coil springs which alternate with the arms of a flange forming part of the input element or of the output element, and with pockets provided on the housing and forming part of the output element or of the input element. One or more antifriction bearings are installed between the input and output elements.

Abstract: A sheave which can be connected to the output shaft of an internal combustion engine in a motor vehicle has a rotary input element, an output element which is coaxial with and rotatable relative to the input element and is provided with a rim for one or more endless belts or chains, one or more bearings between the input element and the output element, a damping unit which opposes rotation of the two elements relative to each other, and an inertial damper which is connected between the output shaft and the input element. The inertial damper has a ring-shaped mass which is at least partially surrounded by and is closely adjacent the rim. The rim, the inertial damper and the damping unit are interfitted in the axial direction of the sheave to contribute to compactness of the sheave.