System for cooling a starting clutch of a continuously variable transmission

A clutch cooling system for cooling a clutch used in combination with a continuously variable transmission having an input variable-diameter pulley and an output variable-diameter pulley, said pulleys each having a fixed sheave and a movable sheave, a belt connecting said pulleys, and a means for controlling axial movement of said input movable sheave and said output movable sheave to alter the effective diameter of said input pulley to provide a continuously variable drive ratio, and to alter the effective diameter of said output pulley to maintain belt tension, said cooling system comprising:

• a pressure controlled spool valve including a housing defining a chamber and a spool movably mounted within said chamber, said housing further defining a notch, and said spool having a leading edge such that as said spool traverses said chamber said leading edge traverses said notch to form a variable orifice therebetween;
• a pressure controlling means for adjusting the pressure applied to a remote end of said spool such that as the pressure applied to said remote end is varied said the leading edge of said spool traverses said notch and the size of said variable orifice is increased;
• a cooling fluid feed line extending from said chamber and a clutch cooling line extending from said chamber such that cooling fluid can flow from said cooling fluid feed line, into said chamber, through said orifice and into said clutch cooling line.

A clutch cooling system for cooling a clutch used in combination with a continuously variable transmission having an input variable-diameter pulley and an output variable-diameter pulley, said pulleys each having a fixed sheave and a movable sheave, a belt connecting said pulleys, and a means for controlling axial movement of said input movable sheave and said output movable sheave to alter the effective diameter of said input pulley to provide a continuously variable drive ratio, and to alter the effective diameter of said output pulley to maintain belt tension, said cooling system comprising:

• a pressure controlled spool valve including a housing defining a chamber and a spool movably mounted within said chamber, said housing further defining a notch, and said spool having a leading edge such that as said spool traverses said chamber said leading edge traverses said notch to form a variable orifice therebetween;
• a pressure controlling means for adjusting the pressure applied to a remote end of said spool such that as the pressure applied to said remote end is varied said the leading edge of said spool traverses said notch and the size of said variable orifice is increased, said pressure controlling means including a solenoid valve, a pressure feed conduit leading from a pressure source to said solenoid valve, and a pilot pressure conduit extending from said solenoid valve to said remote end of said spool valve;
• a cooling fluid feed line extending from said chamber and a clutch cooling line extending from said chamber such that cooling fluid can flow from said cooling fluid feed line, into said chamber, through said orifice and into said clutch cooling line;
• said spool including a slot which allows minimum flow from said cooling fluid feed line to said clutch cooling line when said spool is positioned such that said leading edge does not coincide with said notch and no orifice is formed;
• and
• a means for regulating clutch slippage wherein during a given amount of clutch slippage a predetermined electrical signal is sent to said pressure controlling means resulting in a given pressure being applied to said remote end of said spool.