Electro-viscous fan clutch with snap action spring valve element for control of fluid gate

摘要

An electro-viscous hydraulic clutch for a fan clutch in which a control arm for controlling the fluid to a shear zone of the fluid clutch is incorporated in an over-center spring which hinges on the pump plate for snap action operation. The control arm is actuated by an electromagnetic device which is mounted either on a fan clutch cover plate or on the fan clutch shaft pole. This invention features low actuating force, snap action control arm operation and integral spring return. The spring return disengages the clutch when the solenoid or coil power is removed.