Viscous clutch assembly for torque transmission in motor vehicle

A viscous clutch assembly adapted for installation in a torque transmission system for effecting a drive connection between a pair of rotary members coaxially arranged for relative rotation, said viscous clutch assembly comprising first means for generating a viscous resistance force in response to relative rotation between said rotary members, second means cooperable with said first means and being provided for converting the viscous resistance force into a thrust force, third means comprising a clutch mechanism cooperable with said second means and engageable in response to the thrust force from said second means for establishing the drive connection between said rotary members, and fourth means cooperable with said first means for increasing and decreasing the generated viscous resistance force in said first means in accordance with a difference in torque between said rotary members, and independent of a value of a speed differential between said rotary members.