Ball ramp driveline clutch actuator with biasing element

A ball ramp actuator for rotationally coupling two rotating elements comprising:

• an input element driven by a prime mover and rotating about an axis of rotation;
• an output element having an axis of rotation coaxial with said axis of rotation of said input element for rotating an output device;
• a ball ramp mechanism for generating an axial movement comprising;
• an annular control ring having an axis of rotation, said control ring having a plurality of circumferential control ramps formed in a first face of said control ring, said control ramps varying in axial depth, an equivalent number of rolling elements one occupying each of said control ramps, an actuation ring having an axis of rotation coaxial with said axis of rotation of said control ring, said actuation ring having a plurality of actuation ramps substantially identical in number, shape and radial position to said control ramps where said actuation ramps at least partially oppose said control ramps and where each of said rolling elements is contained between one of said actuation ramps and a respective control ramp, said control ring being axially and rotationally moveably disposed relative to said actuation ring;
• a carrier ring frictionally rotationally coupled to said control ring;
• a first gearset having an annulus nonrotatably connected to said input element where a plurality of first planet gears engage said annulus;
• a second gearset having an annulus electromagnetically coupled to said control ring, and a sun gear rotatably driven by said output element where a plurality of second planet gears couple said sun gear to said annulus;
• a control clutch for frictionally coupling said control ring to said input element;
• a coil for inducing an electromagnetic field in said control clutch to frictionally couple said carrier ring to said control ring;
• a coil plate disposed adjacent to said coil and rotating with said output element;
• a clutch member nonrotatably connected to said control ring contacting said coil plate;
• and
• a biasing means for maintaining a minimum separation between said clutch member and said coil plate when said coil is not energized.