Remote sensing fan drive

Claim 1

A viscous fluid clutch rotatable about an axis of rotation and adapted to be controlled by a sensing element spaced apart from the fluid clutch comprising an axially extending shaft disposed on the axis of rotation, a first member secured to said shaft for rotation therewith, a second member rotatable relative to said first member, shear surfaces disposed on said first and second members and forming an operating chamber therebetween, a fluid storage chamber disposed adjacent to said operating chamber, valve means effecting selective communication between said storage chamber and said operating chamber and including a valve member having a first and a second position, one of said positions providing for fluid communication between said storage chamber and said operating chamber and the other of said positions blocking such fluid communication, fluid means disposed within said storage chamber and being selectively displaced into said operating chamber when said valve member is in said one position to provide in said operating chamber a medium to transmit rotational motion from one of said members to the other of said members, pump means in said operating chamber to displace said fluid means from said operating chamber to said storage chamber, an electromagnetic coil having an axial opening therein defined by an inner surface of said coil, and an armature member having an outer surface located at least partially within said axial opening of said coil with said outer surface of said armature member being disposed contiguous to said inner surface of said coil, said armature member being movable in an axial direction upon energization of said coil, said armature member being operatively connected to said valve member to effect movement of said valve member between said first and second positions in response to energization of said coil, said coil being operable to establish a flux path to move said armature in an axial direction and wherein said flux path sequentially passes from said coil to said armature and back to said coil without passing through a substantial portion of said shaft, said shaft including an axially extending opening therein disposed coaxial to said axis of rotation and said armature member being located in said axially extending opening in said shaft, and said shaft further including a cavity disposed therein coaxial to said axis of rotation, said coil being disposed in said cavity with said axial opening in said coil being disposed coaxial to said axis of rotation.