Continuously variable fan drive clutch

A clutch assembly for a cooling fan in an engine, the clutch assembly being of size capable of fitting an envelope between the engine and the cooling fan associated with a cooling radiator, the clutch assembly comprising a compact housing having a belt drive input and a fan hub generating an output wherein the housing has a diameter equal to or less than about 9.8 inches and an axial length of equal to or less than about 7.3 inches so the housing may be positioned between the radiator and the engine and wherein the output is at least 55 horsepower at 2100 rpm;

• and a plurality of juxtaposed driving and driven wet clutch plates in a clutch chamber in the housing, operatively connected to the compact housing and the fan hub respectively, the clutch plates having a fully engaged position in which the belt drive input and the fan hub are driven at the same speed, a disengaged position in which the belt drive input is released from the belt drive input and partially engaged positions in which the fan hub is driven at a speed between the speeds of the engaged and disengaged positions, the clutch assembly having a lubricating fluid passageway therein for communicating lubricating fluid to the clutch chamber, the housing including a cover section interfit telescopically with the belt drive input, the belt drive input and the cover section being joined by a snap ring without any threaded fasteners.

A clutch assembly for a cooling fan in an engine, the clutch assembly being of size capable of fitting an envelope between the engine and the cooling fan associated with a cooling radiator, the clutch assembly comprising a compact housing having a belt drive input and a fan drive hub generating an output wherein the housing has a diameter equal to or less than about 9.8 inches and an axial length of equal to or less than about 7.3 inches so the housing may be positioned between the radiator and the engine and a plurality of juxtaposed driving and driven wet clutch plates in a clutch chamber in the housing, operatively connected to the compact housing and the fan hub respectively, the clutch plates having a fully engaged position in which the input and hub are rotated at the same speed, a declutched position in which the drive hub is stationary, and continuously variable positions therebetween in which the drive hub is rotated at continuously variable speeds;

• the clutch assembly having a lubricating fluid passageway therein for communicating lubricating fluid to the clutch chamber wherein the clutch plates have sufficient surface area and receive sufficient flow of lubricating fluid such that the clutch assembly is capable of dissipating 10 horsepower in heat while in the continuously variable positions;
• and wherein the driving clutch plates are splined along an inner annular surface of the housing at the radial periphery of the clutch chamber to thereby maximize clutch plate area for the given diameter of the housing.