Electromagnetically actuated power transmitting assembly

摘要

An electromagnetically actuated power transmitting assembly has a cup shaped pulley structure mounted for rotation about the input shaft of a power driven device. The pulley structure has an outer annular driven portion for engaging an endless flexible driving element such that engine driven movement of the driving element rotates the pulley structure. The outer annular portion has ferromagnetic material along at least an internal diametrical periphery thereof to allow magnetic flux to flow therethrough. A one-piece flux carrier/mounting structure is formed from ferromagnetic material and has a mounting portion fixedly mounted to the power driven device and an annular flux carrier portion nested within the cup shaped pulley structure to allow the pulley structure to rotate relative to the flux carrier and to allow magnetic flux to flow therebetween. An annular magnetic coil for inducing a field of magnetic flux is fixedly mounted in the carrier portion. A selectively movable clutch has a magnetically attractable disc portion and a biasing member biasing the disc portion to a disengaged position. The clutch is mounted such that energizing the coil induces a magnetic flux which overcomes the bias and selectively moves the disc portion from the disengaged position to an engaged position wherein the clutch couples the pulley structure and the input shaft for rotation. De-energizing the coil enables the biasing member to move the disc portion to the disengaged position de-coupling the pulley structure the input shaft to allow the pulley structure to rotate relative thereto.