ELECTROMAGNETICALLY ACTUATED PULLEY ASSEMBLY

摘要

An electromagnetically actuated power transmitting assembly (8) has a cup shaped pulley structure (30) mounted for rotation about the input shaft (14) of a power driven device (10). The pulley structure (30) has an outer annula r driven portion (32) for engaging an endless flexible driving element (12) su ch that engine driven movement of the driving element rotates the pulley structure (30). The outer annular portion (32) 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 (60) is formed from ferromagnetic material and has a mounting portion (62) fixedly mounted to the power driven device and an annular flux carrier portion (64) nested within the cup shaped pulley structure (30) to allow the pulley structure to rotate relative to the flux carrier and to allow magnetic flux to flow therebetween. An annular magnetic coil (70) for inducing a field of magnetic flux is fixedly mounted in the carrier portion (64). A selectively movable clutch has a magnetically attractable disc portion (48) and a biasin g member (50) biasing the disc portion to a disengaged position. The clutch is mounted such that energizing the coil (70) induces a magnetic flux which overcomes the bias and selectively moves the disc portion from the disengage d position to an engaged position wherein the clutch couples the pulley structure (30) and the input shaft (14) for rotation. De-energizing the coil (70) enables the biasing member (50) to move the disc portion (48) to the disengaged position de-coupling the pulley structure (30) the input shaft (1 4) to allow the pulley structure (30) to rotate relative thereto.