Torque transfer apparatus using magnetorheological fluids

A torque transfer apparatus for a motor vehicle having a torque supply, a first propshaft and a second propshaft, said torque transfer apparatus comprising:

• an input shaft rotatably driven by said torque supply and coupled to said first propshaft;
• an output shaft coupled to said second propshaft;
• a magnetorheological fluid coupling disposed between said input shaft and said second propshaft comprising:
• a first plate rotatably driven by said input shaft;
• a second plate coupled to said output shaft and spaced apart from said first plate;
• a magnetorheological fluid, said first and second plates being immersed in said magnetorheological fluid;
• circuit means for applying a magnetic field to said magnetorheological fluid to variably control the transfer of torque between said first plate and said second plate;
• and
• control means for variably controlling the magnitude of said magnetic field applied by said circuit means in response to an operating condition of said motor vehicle.

A transfer case for use in a motor vehicle having a torque supply, a first driveline and a second driveline, said transfer case comprising:

• a first shaft driven by said torque supply and coupled to said first driveline;
• a second shaft coupled to said second driveline;
• a magnetorheological fluid coupling disposed between said first shaft and said second shaft comprising:
• a first plate coupled for rotation with said first shaft;
• a second plate coupled to said second shaft;
• a magnetorheological fluid, said first and second plates being immersed in said magnetorheological fluid;
• circuit means for applying a magnetic field to said magnetorheological fluid to variably control the transfer of torque between said first plate and said second plate;
• and
• control means for variably controlling the magnitude of said magnetic field applied by said circuit means in response to at least one of a plurality of conditions comprising a rotational speed of said first shaft, an amount of torque transferred by said first shaft, a rotational speed of said second shaft, an amount of torque transferred by said second shaft, a speed of said motor vehicle, a steering direction of said motor vehicle, a throttle position of said motor vehicle, a gear position of said motor vehicle, and a brake position of said motor vehicle.