Multispeed drive for engine-cooling fan

摘要

A multispeed drive for a motor-cooling fan has a shaft extending along and defining an axis and a planetary transmission including a sun gear fixed on the shaft, a planet element rotatable about the axis on the shaft and carrying planet gears meshing with the sun gear, and a ring element rotatable about the axis on the shaft and meshing with the planet gears. A fan is rotatable about the axis and fixed to one of the elements and an input member is also rotatable about the axis on the shaft adjacent the fan. Concentric electromagnetic clutches each have an output side connected to a respective one of the elements and couplable to the input member for closing and coupling the respective output side to the input member and for opening and decoupling the respective output side from the input member. Thus when both clutches are open the fan is decoupled completely from the input member.