PTO lube control system

A lubrication system for a power take off (PTO) assembly, the PTO assembly having an input shaft driven by a power source, an output shaft, a transmission for transmitting torque from the input shaft to the output shaft, and a disconnect unit for selectively coupling and uncoupling the input shaft from the transmission, the lubrication system comprising:

• a component lube circuit for lubricating a component of the PTO assembly;
• a pump for supplying lubricant from a reservoir;
• and
• a lube control valve for controlling communication of lubricant from the pump to the component lube circuit, the lube control valve being operatively coupled to the disconnect unit so that when the disconnect unit is engaged the lube control valve blocks communication from the pump to the component lube circuit, and when the disconnect unit is disengaged the lube control valve communicates the pump to the component lube circuit;
• a transmission lube circuit for lubricating the transmission;
• and the control valve communicating lubricant to the transmission lube circuit when the disconnect unit is engaged and disengaged;
• the control valve comprising a housing having a valve bore therein, a pump port communicating the valve bore with the pump, a first port communicating the valve bore with the component lube circuit, the first port extending though an end wall of the valve bore, and a second port communicating the valve bore with the transmission lube circuit;
• and a valve spool slidable in the valve bore and coupled to the disconnect unit, the spool being movable from a first position wherein communication is open between the pump port and the second port and communication is closed between the pump port and the first port, to a second position wherein communication is open between the pump port and the second port and communication is open between the pump port and the first port, the valve spool having a hollow body and a head wall at one end thereof, the head wall having a passage extending therethrough, one end of the passage being in communication with the first port, an other end of the passage being surrounded by a valve seat, the valve spool having a sump passage extending therethrough and communicating an interior of the valve spool with a fluid reservoir;
• a valve ball received by the valve spool and engagable with the valve seat;
• and a spring received by the valve spool and biased to urge the valve ball towards with the valve seat, the valve ball being movable away from the valve seat to thereby limit pressure in the first port.