Torque converter

Typically an axial mounted enclosed circular housing mounted to an "output" shaft consisting of a "stator like" outer hollow doughnut with a separate, non-mechanically coupled, internal fan or turbine mounted to an input shaft and contained inside a viscous fluid or oil within the "doughnut" or stator. The fluid coupler or torque converter then acts on the principal of turbulence and resistance created by the rotation of the fan inside the stator using the fluid or oil as a coupling medium to induce a torque to turn the stator. The stator may not be designed to be smooth on the inside surface, but ridged or otherwise altered to harness, capture, or create increased turbulence with the fan.

The faster the fan turns, the more turbulence is created, which acts on the larger internal surface area of the stator to begin rotating it.

The "fan" or turbulence inducing device within the "stator" may be more of a more simple, straight forward design, or it may be more complex consisting of gear multipliers, and rollers to increase or manipulate the turbulence curves and effects.

In principal as RPMs are reduced, the less coupling between the inner fan and the outer stator allowing the input shaft to remain spinning, while the output shaft can be stationary in effect creating a hydraulic slippage clutch with no hard surfaces, belts, chains, or other solid devices to wear against each other, except bearings needed to hold the fan inside the stator, and to mount to the input and output shafts.